Effective Air Cooling Guide (Part II) - Myths, Old Rituals, and Analysis


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[FONT=arial]I. Disclaimer[/FONT]
[FONT=arial]II. Foreword[/FONT]
[FONT=arial]III. Case Pressure[/FONT]
[FONT=arial]1. Debates, Facts and Myths[/FONT]​
[FONT=arial]1.1. Positive Case Pressure[/FONT]​
[FONT=arial]1.2. Negative Case Pressure[/FONT]​
[FONT=arial]2. Conclusion[/FONT]​
[FONT=arial]IV. Case Acoustics, Noise, and Mental Health[/FONT]
[FONT=arial]1. Mitigation Procedures: Easy Way Out[/FONT]​
[FONT=arial]1.1. Eliminating The Source Of Noise[/FONT]​
[FONT=arial]1.2. Using Components That Produce The Least Noise[/FONT]​
[FONT=arial]1.2.1. Fan Bearings[/FONT]​
[FONT=arial]1.2.2. Fan Controllers[/FONT]​
[FONT=arial]1.2.3. Quiet Drives[/FONT]​
[FONT=arial]1.2.4. Quiet PSUs[/FONT]​
[FONT=arial]1.2.5. Quiet GPUs[/FONT]​
[FONT=arial]1.2.6. Quiet Cases[/FONT]​
[FONT=arial]1.2.7. Water Cooling Kits[/FONT]​
[FONT=arial]1.3. Kill All The Noise Before It Reaches Your Ears[/FONT]​
[FONT=arial]1.4. Mr. Cheapskate's Effective Methods[/FONT]​
[FONT=arial]2. Case Layout Contributing To Noise[/FONT]​
[FONT=arial]2.1. Cable Management[/FONT]​
[FONT=arial]V. Some Old Rituals, Healthy Traditions[/FONT]
[FONT=arial]1. Using Thermal Paste: The Right Way[/FONT]​
[FONT=arial]1.1. Fool-proof: The Good Ol' 1-drop-per-chip Method[/FONT]​
[FONT=arial]2. Beware Of These Sins[/FONT]​
[FONT=arial]3. The Million Dollar Question[/FONT]​
[FONT=arial]VI. Fan Placements[/FONT]
[FONT=arial]1. Some Inadvisable Arrangements[/FONT]​
[FONT=arial]2. Some Ideas[/FONT]​
3. Drive Cooling​
[FONT=arial]VII. Supplementary Cooling Accessories/Attachments[/FONT]
[FONT=arial]1. RAM Heat-spreaders[/FONT]​
[FONT=arial]2. Add-on PCI Slot Fans/Coolers[/FONT]​
3. Custom Chipset Coolers (Active)​
VIII. Summary

[CENTER][FONT=arial]The content of this guide/article is based on observation, research, and repeated self-experiments, and is subjected to change without notice. By reading this guide you hereby also agree to comply with TechSpot's Terms of Service. While effort has been taken to make this guide's content accurate and unbiased, please use your discretion while using the information hereon. Its applicability and compatibility to your system is not guaranteed. Neither TechSpot nor the author can be held responsible for any damages, material or otherwise, to any entity, living, dead, or undead, by errors, human or otherwise. The author has written this guide out of kindness of his heart and will to share knowledge, and has no commercial interest in it. Information provided is for personal and non-commercial use only. The author is to be duly credited if this article is redistributed/ copied anywhere other than TechSpot. Users are permitted to link or quote to this article. All digital content, brand, product, and company names, licensed or otherwise, are properties of their respective owners.[/FONT][/CENTER]
[CENTER][FONT=arial]© 2012[/FONT][/CENTER]
[FONT=arial]Hello there! Sorry for the delay, if I made you wait too long. Been busy. The third part may take a bit longer. Anyway, this is the second part (first part here) of the air-cooling guide by me, based on observation, research and experiments. Hope you enjoy it. Leave you feedback in your replies. Your suggestions, praise, and constructive criticism is welcome.[/FONT]
[CENTER][FONT=arial]Case Pressure[/FONT][/CENTER]
[CENTER][FONT=arial]Debates, Facts and Myths[/FONT][/CENTER]
[FONT=arial]On dedicated overclocking and modding forums, and even here at TechSpot, there are often debates over which case pressure is better either in terms of cooling or cleaning. To begin with, case pressure is the pressure co-efficient of a case, determined by the ratio of volume of air moving into the case to the volume of air moving out of the case. Positive case pressure does not mean all intakes, no exhausts, and negative case pressure does not mean all exhausts, no intakes. Case pressure cannot be determined by the mere numbers of fans. Example, a single 230 mm intake would still move more air than 2x 80 mm exhausts, creating positive case pressure, instead of the expected negative pressure when hearing just the number of fans.[/FONT]
[FONT=arial] To identify which case pressure you are currently having, add your individual intake fans’ specified CFM rating (usually mentioned on the fan housing or motor itself) for your total intake CFM, and compare it to you total exhaust CFM addition. If the total intake CFM is greater than your total exhaust CFM, you have positive case pressure, and vice-versa.[/FONT]
[FONT=arial]However, be warned that some manufacturer specs can be misleading, or often grossly miscalculated/overstated. For ruling our such errors, it is advisable to google for reviews on your particular fan or aftermarket CPU cooler. It is recommended that you read what reliable and reputed hardware review sites such as Tom's Hardware, AnandTech and our very own TechSpot have to say about that product, and whether or not the specifications are authentic.[/FONT]
[FONT=arial]Bear in mind that using filters, dust covers, and other obstructions to the intakes reduce specified CFM, so this calculation method is not foolproof. So if you are using filters over intakes, and the intake CFM is less than 3x the exhaust CFM, you might as well have negative case pressure.[/FONT]

[CENTER][FONT=arial]Positive Case Pressure[/FONT][/CENTER]
[FONT=arial]Often said to be better than negative case pressure in terms of dust accumulation and cooling, positive case pressure does have its cons, too.[/FONT]
[FONT=arial]· Slower dust accumulation when intakes filtered: Air may actually be leaking out through gaps. Atmospheric dust cannot go against airflow, so it is kept out.[/FONT]
[FONT=arial]· Effective in the short term: The cool air (comparatively) being blown in successfully keeps temperatures down for some time after start-up. But:[/FONT]
[FONT=arial]· Severely inefficient in the long run: More air is going in than out. So air isn’t vacated fast enough. That is, it stays inside near the heated components longer, and absorbs more heat, but in the process heats up other components as it passes over them on its way out. In tight, enclosed, or obstructed spaces, such as between RAM sticks, drives, GPU’s and particularly the top-front section of the case, hot air-pockets are formed when a system operates for longer periods of time, making matters worse. Though good airflow and cable management can significant reduce this, it cannot fully eliminate it.[/FONT]

[CENTER][FONT=arial]Negative Case Pressure[/FONT][/CENTER]
[FONT=arial]This may seem like being a devil’s advocate, but negative case pressure, I’ve observed, has often been demonised. To justify my statement, here’s a look at its pros and cons:[/FONT]
[FONT=arial]· Lower temperature-time graph curve: And by that I mean a slower rise in temperatures over extended operational time. After 30 minutes of IntelBurnTest with positive case pressure, CPU temperature rose from 46°C to 57°C. With the same test profile, but negative pressure, temperatures rose from 39~40°C to 46~47°C in 30 minutes. That’s a 10°C drop in the max temps, and a 6.5°C drop in idle temps. Impressed, I let it go on for another 30 minutes, and only saw a rise to 47~48°C. So by that pattern it might as well be a reduction in the max. temperature “wall”. IntelBurnTest is very intensive, so I couldn’t provide any screenshots, sorry. And the temperatures fell very rapidly once the test was over.[/FONT]
[FONT=arial]· No* hot air-pockets inside: The partial vacuum left behind by the air which is vacated from the case can’t be filled fast enough by the filtered intakes (*depends on CFM) and air from other gaps. To fill it, the remaining air from all around the case begins moving into its place, with it eliminating all air-pockets. This air, if the fans are appropriately placed, the cool air gets quickly vacated from the case, absorbing heat from other parts on its way, and the cycle continues.[/FONT]
[FONT=arial]· Accelerated Dust Accumulation: Not that I noticed it in my test setup, but many report negative case pressure to increase the rate at which dust accumulates. Thus, a case with negative pressure needs to be cleaned more often than one with positive pressure. However, I personally find this quite baseless. For significantly more dust to build up, it would require significant gaps, like unoccupied fan mounts, open expansion covers and drive bezels, etc., which is rarely the case.[/FONT]

[CENTER]Take off the filters on negative pressures for half a month, and look what happens. See clear track my finger has left in the dust?[/CENTER]
[FONT=arial]If the front panel is in the form of a mesh, like that on the CoolerMaster Centurion, but when unfiltered…it’s a different story. Either way, here’s what we do to counter gaps of all sizes:[/FONT]
[FONT=arial]1) Get some Scotch Brite Scouring Pads (the thin variety if you will, but the sponge variety will do if you can’t get it) from your local 99 Cents store or Wal-Mart.[/FONT]​
[FONT=arial]2) Carefully and evenly slice them to make them thinner. As thin as possible, but nothing above 3mm. Pull off any thick clumps. Clip off any stray, protruding fibers.[/FONT]​
[FONT=arial]3) Cut this as needed to cover the gaps. Tape it in place.[/FONT]​
[FONT=arial]This may need a little dexterity. If you are uncomfortable doing this, you may consider using pre-made filters cut-to-size, but it serves less purpose than Scotch Brite.[/FONT]
[FONT=arial]This Scotch Brite interior lining serves a triple purpose: (1) Allowing in cool air, (2) Keeping out dust and (3) acoustic dampening (explained later).[/FONT]

[FONT=arial]As we saw, negative case pressure is the winner when it comes to performance computing and therefore cooling. Its downsides, if any, can easily be countered and negated, unlike positive case pressure. So if you can, use it.[/FONT]
[FONT=arial]That being said, let’s move on to something that affects any kind of case pressure: noise.[/FONT]
[CENTER][FONT=arial]Case Acoustics, Noise, and Mental Health[/FONT][/CENTER]
[FONT=arial]Not many need an introduction to the importance of quiet case. While newer and regularly maintained computers may be sufficiently quiet, some older or poorly maintained computers may literally sound like hair-dryers. Technically speaking, noise is unwanted sound. When computer cases are concerned, this noise is varied – from a constant or throbbing whirr to a high-pitched wheeze. Either way, according to my observation, constant whirring sounds can lead to mental insanity.[/FONT]

[CENTER][FONT=arial]Mitigation Procedures: Easy Way Out[/FONT][/CENTER]
[FONT=arial]There are three approaches to countering noise: (1) Eliminating the source of noise, (2) Use components that produce the least noise, and (3) Kill all the noise before it reaches your ears.[/FONT]

[CENTER][FONT=arial]1) Eliminating The Source Of Noise[/FONT][/CENTER]
[FONT=arial]This usually means setting up a passive cooling system. No fans at all. The entire cooling system depends on heatsinks and natural convection. Don’t get too happy though – it’s not for modern computers. Old computers didn’t run at high speeds, so didn’t generate much heat. Modern computer run tremendously faster (needless to explain) than their forerunners, and thus generate much more heat. So while this would’ve been (and actually was) the perfect solution for the PCs then, it isn’t now.[/FONT]
[FONT=arial]Another aspect is drive spins. HDDs’ and CD-ROMs’ motors spin to read and write. This creates vibrations. These vibrations are transferred to the bay and then the case, causing some noise. Though modern drives often use fluid bearings to reduce noise, like the Seagate Barracuda, then rarely beat the performance of SSDs. But the SSDs are currently having compatibility issues on certain hardware, and are now surrounded by skepticism. So it’s advisable to wait for these issues to be resolved before investing in anything. Not much can be done about CD-ROMs for now, other than using a USD static drive instead. To reduce or deaden these vibration, the drives are ‘isolated’ with sophisticated drive isolators/acoustic kits (sometimes including cooling mechanisms too, especially for high-RPM drives) or something DIY (usually rubber grommets or sponge cushions). Same applies for fans, too.[/FONT]
A silicon grommet suspending a HDD.[/FONT]

[CENTER][FONT=arial]2) Use Components That Produce The Least Noise[/FONT][/CENTER]
[FONT=arial]It’s self-explanatory. We’ll begin with fans.[/FONT]

[FONT=arial]Fan Bearings:[/FONT]
[FONT=arial]1) Sleeve Bearing: These are the most common type. Cheap and easily available, but the most noisy. Common sizes (diameters) are 80 mm and 120 mm, with 230 mm on the rise.[/FONT]
[FONT=arial]2) Ball Bearing: A more expensive and quieter version, with the same sizes as sleeve bearing fans.[/FONT]
[FONT=arial]3) Fluid Bearing: An even more expensive alternative, with even less noise, and somewhat rare. Usually used in high-end HDDs. Same sizes.[/FONT]
[FONT=arial]4) Magnetic bearing: By far the most expensive and exotic version, the fan blades “float” due to magnetic levitation, make it virtually inaudible.[/FONT]
[FONT=arial]As usual, larger diameter = quieter operation[/FONT]​

[FONT=arial]Fan Controllers:[/FONT]
[FONT=arial]Most may be familiar with these, but for those who are not, here's a quick explanation:[/FONT]
Wikipedia said:
Fan controllers can be used to slow down fans and to precisely choose fan speed. Fan controllers can produce a fixed fan speed using an inline resistor or diode, or a variable speed using a potentiometer or Pulse Width Modulation (PWM). Resistor-based fan control feeds the fan a lower voltage, while PWM fan control rapidly cycles between feeding the fan full voltage and no voltage. PWM fan control reduces rotational speed, and is the easiest and most efficient option for motherboards which have PWM fan headers. This is because PWM fans in conjunction with the motherboard chipset obtain temperature data from Digital Temperature Sensors on the CPU itself. All PWM fans are four pin, and if plugged into a conventional three pin supply will operate at full speed just like a three pin fan.
As seen, it doesn't take much. The lowered voltage reduces the RPM (rotation speed) of the fan when idle, reducing the noise caused by turbulence and inevitable mechanical noise. This is especially effective in systems which aren't continuously under heavy load. Most of the fans you get now come with a 4-pin connector, where the fourth pin it meant for fan control (see next section for details on software-controlled PWM). You also have the option of a DIY fan controller, if you're interested.[/FONT]

[FONT=arial]Quiet Drives:[/FONT]
[FONT=arial]These mean fluid-bearing motors. These usually come standard for HDDS. As always, SSDs are the quietest, given they have no moving parts inside. As always, the choice is yours.[/FONT]

[FONT=arial]Quiet PSUs:[/FONT]
[FONT=arial]PSUs are made quieter through the use of higher efficiency (which reduces waste heat and need for airflow), quieter fans, more intelligent fan controllers (ones for which the correlation between temperature and fan speed is more complex than linear), more effective heatsinks and through designs which allow air to flow through with less resistance.[/FONT]
[FONT=arial]For a given power supply size, more efficient supplies, such as those certified 80 plus, generate less heat.[/FONT]

[FONT=arial]Quiet Cases:[/FONT]
[FONT=arial]These are a combination of most if not all of the above factors. Generally considered high-end and expensive, the price may be a bit higher than the individual parts put together.[/FONT]

[FONT=arial]Quiet GPUs:[/FONT]
[FONT=arial]These are passively cooled ones, requiring lesser power (and giving less..). No fans, no noise. Powercolor GoGreen GPUs are a good option, particularly the PCS (Professional Cooling System) ones. Energy saving, cooler, and quiter. But these usually aren't high-end devices, so check your needs first.[/FONT]

[FONT=arial]Water Cooling Kits:[/FONT]
[FONT=arial]Earlier, water cooling used to be quiet noisier than air-cooling, but recent developments in pump technologies have made the future brighter (the H80 is a good example). Not only they reduce noise, but also gives better cooling performance. Only drawback is that it reduces savings. For a more comprehensive look into water cooling, you may want to read DivideByZero's water-cooling guide.[/FONT]

[CENTER][FONT=arial]3) Kill All The Noise Before It Reaches Your Ears[/FONT][/CENTER]
[FONT=arial]Ever been to a concert or cinema hall? Observed the walls? Those paddings are for ‘acoustic dampening’. Sound waves hit these porous/thick layers, they slow down, and are thus “deadened”. So less noise escapes the case. Mounting the fans on the case generates vibrations when the fans spin, making noise. However, this can be countered by ‘isolating’ the fans. Here’s how:[/FONT]
[FONT=arial]1) Get some rubber or silicon grommets (silicon is a bit expensive) and some soft material like foam sheets from a craft store or thick Scotch Brite Pads from 99Cents or Wal-Mart. You’ll need some duct or plastic (transparent) tape too. Scissors/cutting knives for cutting the sheets and grommets. A measuring ruler. A steady hand, and some patience.[/FONT]​
[FONT=arial]2) Unscrew and detach any fans, lighting, or other eye-candy or components (other than the motherboard, everything that’s on it, and the drives, which can have trouble fitting in if raised/flanked by sheets). Line the inside of the side panels of your case with it (you can even cover the whole inside if you like, provided you use Scotch Brite. That’ll also fulfill the filtering function we saw in the Negative Case Pressure: Cons Section in the Case Pressure Chapter. Just removes the need to cut individual sheets. However, this makes it more difficult/expensive to clean replace the filters). Cut to fit exactly. Note that this is not meant to cover the fan intakes as filters, but only the smaller gaps and openings, and act as a sound dampening barrier for the whole case.[/FONT]​
[FONT=arial]3) You unscrewed your fans before taping the sheets in place, right? Take some grommets and place them between the fan screw holes and the side panel (or any panel it is screwed onto). Now screw the fans back on. Firmly, but not so tight that you’ve defeated the sole purpose of isolation.[/FONT]​
[FONT=arial]4) You can even consider suspending the fans inside the case, so that their sound is more muffled due to the case and the padding we added stopping the sound waves. But this needs quite a bit of craftiness, and can be a bit exotic, so I’m leaving out further details on the subject.[/FONT]​

[CENTER][FONT=arial]4) Mr. Cheapskate's Effective Methods[/FONT][/CENTER]
[FONT=arial]Some hardware features such as PWM in some cases can only be activated/implemented by enabling specific software settings.[/FONT]
[FONT=arial]1) To use fan-speed-control on AMD-based systems, enable the BIOS setting called "Cool'n'Quiet", while for Intel-based systems it's "EIST". Refer to you motherboard's manual for specific instructions and notes on the feature, like whether it supports it in the first place or not. For its namesake, this reduces both noise and temperature (not to mention it reduces electricity bills...;)).[/FONT]​
[FONT=arial]2) For those who know what I'm talking about, and what they are doing, underclocking (reverse of overclocking), especially undervolting can have a huge effect on temperatures, and thereby noise.[/FONT]​
[FONT=arial]3) Yank out those ugly grilles! Believe it or not, those stock stamped-out mesh/honeycomb/drain grilles not only seriously restrict airflow, but also create a lot of noise. Wire grilles are the best in both airflow performance and noise. Having no grilles reduce noise even further, but for child, pet and finger safety, I recommend you leave them in place. So just replace any other grille designs with wire-grilles. Good-looking custom grilles may look cool, but not necessarily work efficiently.[/FONT]​
[FONT=arial]4) Defragment your hard-drives regularly. This improves system performance, and reduces the seek time required by the drive, therefore reducing noise.[/FONT]​
[FONT=arial]5) Improve you cable-management and tidiness (see the next section).[/FONT]​
[FONT=arial]6) Get rid of that dust! Increased temps make the cooling system work harder, increasing noise. In case you've forgotten how to, here's the first part of the guide.[/FONT]​
7) Acoustic Dampening Lining on the inside of the case (anywhere air-filtering is not involved) can not only be made of Scotch Brite sheets, but also Silicon sheets which are quite versatile in terms of color, sizes, fitting, flexibility, and whatnot.​
Since this is a DIY procedure, I'll be explaining this in Part III.
Also, Air Conditioner Foam can also be used where Scotch Brite doesn't meet the requirements, generally in terms of size. Something similar is found in the CoolerMaster Centurion case.​
[CENTER][FONT=arial]Case Layout Contributing To Noise[/FONT][/CENTER]
[FONT=arial]I had this crazy experience a few months ago. I was shifting the fans around to see which arrangement works best. When I booted up the system, it sudden started sounding like a hair-dryer. I checked the fans and filters for problems, but to no avail. Confused, I started checking individual parts. Then in a few moments I realized: there was a duct directly opposite to the rear intake, which was the source of the problem. The duct had flat triangular corner supports, which caused turbulence when the air was violently cut through it. I removed the duct, and it went quiet again.[/FONT]
[FONT=arial]So some parts of the case, like ducts or bays, can interfere with the airflow, causing turbulence and leading to noise. Poor cable management, too, can be bad for a case. Not only does it disrupt airflow, but it also adds to turbulence in some cases.[/FONT]

[CENTER][FONT=arial]Cable Management[/FONT][/CENTER]
[FONT=arial]From rounding IDE cables or using round ones, to sleeving or zip-tying the SATA and other power cables, this is quite important in terms of acoustics, cleanliness, and aerodynamics. It’s usually simple enough though. IDE cables are a legacy item now, so I can’t delve further into that. Not that I have any to test anything on anyway. So for the SATA and cables and wires coming from the PSU, get some zip-ties from the craft store, and tie them up neatly and elegantly (Don’t force any cables or wires around, they can break internally). You can even tuck them behind the motherboard, but I wouldn’t recommend that for safety reasons. Instead, tuck them into empty drive bays and secure them with zip-ties there. Wherever you secure them, make sure it doesn’t interfere with airflow.[/FONT]
[FONT=arial]Some cases even come with facilities for cable management. If you plan a new build, and can afford high-end cases, look for these features too, in addition to cooling features, ventilation and airflow.[/FONT]

[CENTER][FONT=arial]Some Old Rituals, Healthy Traditions[/FONT][/CENTER]
[FONT=arial]For years now aftermarket thermal paste has been all the rage. Before getting into that, let’s see how thermal paste works. Note that this also applies to water-cooling.[/FONT]
[FONT=arial]Any surface, no matter how visibly smooth, always has microscopic pits and ridges. When mounted in the socket, air gets trapped in these pits, and reduces the surface area in contact with the CPU assembly, and reduces the rate of heat transfer. These pits are therefore filled with thermal paste or thermal grease, which are thermally conductive. They transfer heat from the CPU to the heatsink efficiently, thus improving cooling. Generic pastes consist of micro-ceramics.[/FONT]
[FONT=arial]Aftermarket thermal pastes such as Artic Silver 5, true to its name, even contain silver, a good conductor of heat. And electricity, which makes it somewhat…risky. For explanation, read the next section. But the temperature difference, if any, is usually negligible, whether you use ceramic-based or liquid-metal-based paste. So think before you invest the extra money.[/FONT]

[CENTER][FONT=arial]Using Thermal Paste: The “Right” Way[/FONT][/CENTER]
[FONT=arial]Again, there is no universal answer to this. Everyone has different opinions as to how and how often thermal paste should be applied. Whether you apply it like you butter your bread, or apply it such that the pressure from the heatsink (CPU cooler) automatically spreads it evenly, there are certain do’s and don’ts. Nobody wants to fry their CPU or motherboard, right?[/FONT]

[CENTER][FONT=arial]Fool-proof: The Good Ol’ 1-drop-per-chip Method[/FONT][/CENTER]
[FONT=arial]“Inject” (squeeze/press out) a drop of paste onto the center of the chip. The blob should be no more than about the size of 2 grains of wheat (*not* a pea, but maybe half a pea). Now hold the heatsink over the socket, and evenly lower it into place. It is important that the heatsink does not flatten the paste sideways like a pita-maker hooked on one side, as this would make the spread lopsided. Avoid tilting the heatsink while it presses the paste (I may later add photos to explain this if needed). Now screw the screws into place, diagonally, in an alternating fashion. Tighten the, into place so it firmly sits on the CPU, but don’t over tighten it, lest you warp/damage the motherboard. :/[/FONT]
[FONT=arial]I’ve seen people also use the credit card or blade method. Some even seem to like glove games. But so far I haven’t seen these methods work more effectively than the one stated above. Furthermore, these methods are far too difficult (does not apply to pastry chefs. Just a joke) as it is near-impossible for a novice (or even someone experienced) to gauge the final thickness and cover area of the paste.[/FONT]
[FONT=arial]For a video demonstration on proper thermal paste application, here is an excellent video and its updated version.[/FONT]

[CENTER][FONT=arial]Beware Of These Sins[/FONT][/CENTER]
[FONT=arial]1) Less experienced enthusiasts tend to use too much paste, and drip it onto the motherboard, making it electrically conductive. And then you get a CPU for toast (it’ll look like it too) and paste for butter.[/FONT]

[FONT=arial]2) Too much paste does no good. Anything bigger than one (or two) grain(s) of wheat is inadvisable. It becomes an insulator. And severely cuts down efficiency. Don’t patter the entire base of the heatsink with paste. Don’t turn the CPU package into a cheese pizza either. The actual processor is at the center of the CPU package. But better if you cover at least 70% surface of the package (radius-from-the-center-wise), as it also depends on dissipation. No need to go to the extreme edges.[/FONT]

[FONT=arial]3) Extremes (too much or too less) are more-than-often unnecessary. Too less paste also has negative effects. (If you can read the product code on the chip, it’s too less paste). Thermal paste is meant to fill out the gaps between the (microscopically) pitted surfaces of the processor and the heatsink, to increase the surface area in contact and speed up the heat transfer. If the paste applied is insufficient, the passive-cooling system does not reach its optimal performance. You’ll only be replacing this paste if you detach the heatsink from the socket, which likely won’t be the case if you follow all the necessary steps in the guide or unless you replace the CPU. So don’t be Mr. Scrooge from Duck Tales (unabashed, I still watch it. Don't look at me like that).[/FONT]

[FONT=arial]4) Don't twist and turn the cooler once it presses down and flattens/spreads the paste. It only creates a bigger mess for you to clean up later.[/FONT]

[FONT=arial]5) Check your CPU’s installation manual and/or the paste’s application manual for specific instruction and cautions.[/FONT]
7) Thermal Adhesive: This is an absolute no-no. Thermal adhesive is just like thermal paste mixed with Super Glue. So you basically glue the cooler to the CPU. Some believe this to improve cooling. Which is a myth. As far as I know, there is no difference in temps.
If you use thermal adhesive and ever want to replace just the CPU or cooler, you're stuck with replacing both, or none. Because they are glued together and can't be taken apart.
[CENTER][FONT=arial]The Million Dollar Question[/FONT][/CENTER]
[FONT=arial]Ok, that’s a hyperbole. But so often we come across this question: how often do I need to replace this paste? As stated above, this paste only needs to be replaced when the heatsink is removed from its place, for this inadvertently dislodges the paste. Under normal circumstances, it only needs to be replaced once a few years, when it eventually “dries up” or so they say. Some never even replace it unless they upgrade the CPU or cooler. So once every 5-6 years should be more than enough for everyday use.[/FONT]

[CENTER][FONT=arial]Fan Placements[/FONT][/CENTER]
[FONT=arial]It can be a real pain to figure out the ideal fan placements and configuration for a particular case. Many cases of constant high temps and/or quick rises in temps are caused due to recirculation of hot air into the case. Intakes and exhausts placed too close, or total absence of exhausts are the usual scenario in such cases.[/FONT]
[FONT=arial]Let’s take a quick look at the basics of traditional fan placements.[/FONT]
[FONT=arial]The conventional airflow is designed to take in cool air from the front-bottom, pass it over the components, and move the now-hot air out through the rear-top and roof of the case. The magnitude of the fans involved in this push-pull mechanism decides the case pressure. This is usually effective in cooling the system, considering the basic physics principle that hot air always rises. Then where do things go wrong? Where else? In the often-neglected issues that sum up to something big. Improper cable management disrupting airflow, poor fan configuration/placement causing them to either short-circuit each other, or be too far to work with each other efficiently.[/FONT]
[FONT=arial]There is no one-size-fits-all solution. However, there are specific arrangements which you have to avoid.[/FONT]

[CENTER][FONT=arial]Some Inadvisable Arrangements[/FONT][/CENTER]
[FONT=arial]1) Intake and exhaust too close: That would ‘short-circuit’ the airflow. The cool (assumed) air is moved out before it comes in contact with the components, decreasing cooling capability.[/FONT]
[FONT=arial]2) Intakes at the roof: Hot air will stay at the top. Imagine it being sucked in from the top, onto the components. Not lovely, eh?[/FONT]
[FONT=arial]3) Intakes below the PSU (when PSU is top-mounted, which I personally prefer): For obvious reasons. The hot (no joke) air being expelled from the PSU could be sucked back in, directly onto the CPU. Can you say ‘oven’?[/FONT]

[CENTER][FONT=arial]Some Ideas[/FONT][/CENTER]
[FONT=arial]1) Side intakes: Those pouring cool air directly onto the board and components.[/FONT]
[FONT=arial]2) Lower-front intakes: Cool air brought in, passing over the storage too.[/FONT]
[FONT=arial]3) Quiet fans: For obvious reasons. Quieter fans, lesser noise.[/FONT]
[FONT=arial]4) Filtered intakes: As above, for obvious reasons. Cleaner air, cleaner case, slower dust buildup.[/FONT]

[CENTER]The (Generally) Hottest Component[/CENTER]
One of the biggest issues with cooling is the GPU. This for several reasons. The new long GPU boards divide a case in half. The active components on the circuit board are on the bottom, at the board prevents the normal tendency of heat to rise, effectively creating a puddle of hot air in the bottom of the case. Antec solves this in their 800 gaming case, by supplying vented PCI expansion slot covers. You can actually aggravate this situation by not studying the airflow patterns induced by different capacity and velocity of airflow. In other words, every fan at peak output could conceivably inhibit some cooling potential.

[CENTER]Drive Cooling[/CENTER]​

Try not to use all the HDD slots in a case. It'll cool much better if you use every other mounting slot. Why? Well, convection. Not only this allows better airflow, but also reduces noise caused by turbulence to a certain extent.
There are also supplementary drive coolers as mentioned in the next section. As to how effective they are, well, mileage may vary.

[CENTER][FONT=arial]Supplementary Cooling Accessories/Attachments[/FONT][/CENTER]
[FONT=arial]There are many supplementary cooling accessories/devices available in the market. Let’s take a look at a few of them we commonly come across.[/FONT]

[CENTER][FONT=arial]RAM Heat-spreaders[/FONT][/CENTER]
[FONT=arial]These work on the same principle as CPU/GPU/chipset heatsinks. They dissipate the heat from the chips into the air. These come in various makes and sizes by different manufacturers. As to how effective these are, it depends on how fast your sticks are running, and at what voltage (Joule’s Law, remember?).[/FONT]
[FONT=arial]DDR1 modules are a legacy item now, so we won’t go into the details, but it’s enough to know it won’t be necessary.[/FONT]
[FONT=arial]The Corsair "Vengeance" DDR3 RAM Heatspreader. Notice the high-profile fins at the top.[/FONT]​
[FONT=arial]Under regular circumstances DDR2 RAM modules will not benefit significantly from it. That is because (1) they aren’t running fast enough to need much cooling and (2) even if overclocked, can’t be overclocked to such a high level (yes, too high voltages can also cause instability) to need it.[/FONT]
[FONT=arial]Early DDR3 modules, on the other hand, not only ran at almost twice the speed, but also a considerably high voltage. So these could sometimes benefit a lot, especially when overclocked. However, since most newer DDR3 and DDR4 modules come with lower stock voltages and ingenious solutions such as Kingmax's "invisible" heat-spreader (a micro-dye for dissipation), so heat isn't an issue with them. So if you have a relatively new module, you may not need a heatspreader at all.[/FONT]

A GSkill RipjawsZ Kit, absolutely not interfering (notice the presence of heatspreaders) with the CPU cooler, a Corsair H80 Water-cooling kit. So it's absolutely not a problem to use them if you can

[FONT=arial]Cons: If you have a high-profile heat-spreader (most are) for the earlier DDR3 modules, it severely cuts down your choice of CPU cooler, almost always, if you are one of those who have the DIMM slots too close to the CPU socket. So depending on you rig and CPU cooler selection, it’s your choice to make.[/FONT]

[CENTER][FONT=arial]Add-on PCI Slot Fans/Coolers[/FONT][/CENTER]
[FONT=arial]If you are unfamiliar to these, here’s a glimpse of what the most common slot cooler looks like:[/FONT]
[FONT=arial] [/FONT]

[FONT=arial]A majority use these for cooling add-on expansion cards that don’t come with an OEM cooler, or at least, an active cooler. Other than blocking up available slots and making the case heavier, I haven’t noticed any negative impact when it is configured/placed/installed wisely. However, if it goes anywhere against the welfare of other components’ cooling, you are better off without it. So for these, if you want to and can, use them.[/FONT]

[CENTER][FONT=arial]Custom Chipset Coolers (Active)[/FONT][/CENTER]
[FONT=arial]Then come the chipset coolers. By default most of these are passively cooled. Believe it or not, those Northbridge’s do indeed get quite hot. Not burn-your-finger hot, but hot enough to be less-than-enjoyable. And it is one of the most critical system components. To make sure these (and the components dependent on them) don’t die a horrible death, there are some things you can do.[/FONT]

[FONT=arial]1)Regular de-caking of the chip and/or its heatsink: As explained in the previous part of this guide, dust build-ups are never a pleasant experience for a cooling system. To ensure maximum possible contact with air, they need to be kept dust-free.[/FONT]​
[FONT=arial]2)Smart fan placements and airflow design: No amount of cleaning or high-end thermal paste/fans can help with cooling if you’re passing hot air over the components in the first place. So make sure there is (a) no internal turbulence, (b) no recirculation and (c) no stagnation over the motherboard at any location.[/FONT]​

[CENTER][FONT=arial]Drive Coolers[/FONT][/CENTER]
[FONT=arial]These are quite self-explanatory. A heatsink block for the HDD, either with or without fan(s).[/FONT]
[FONT=arial]Take a look at this impressive line-up for more details.[/FONT]

[FONT=arial]As I have said innumerable times to friends and others seeking help, always think before you buy. When cooling is considered, buying the right parts is of utmost importance. Picking the right chassis, CPU cooler, and case fans lays the foundation of a successful build. No matter how “cool” (pun intended) a cooling component looks, if it doesn’t suit you system or doesn’t provide satisfactory performance, it’s no good. D[/FONT]on't buy too much more performance than you actually need. Keep the overclocking to a minimum. That may require a step up from the cheap CPU you'd like to get away with, but it should "live longer".
[FONT=arial]The purpose of this guide is not to review aftermarket cooling solutions and make purchase recommendations, but to provide a tutorial for those serious about power-computing. As time passes, there will always be newer and better products. In the end, though, only the best will do. The best doesn't necessarily mean most expensive, either. [/FONT]

[FONT=arial]So, for the final part of this guide, which will be more of a DIY guide elaborating practical implementation of air-ducts and other tips‘n’tricks, stay tuned![/FONT]

[CENTER]A PDF version of the guide is available for download below in the attachments. Hope it helps![/CENTER]
[CENTER]Alternative download mirror from my Dropbox.[/CENTER]


Version 1.5 (November 20, 2012)
Thanks to our member captaincranky:
-Added info about the GPU's contribution to airflow layout​
-Added info about Drive Cooling​
-Added info about air-conditioner foam for sound dampening​
-Added some points to Summary​

Version 1.4 (July 16, 2012)
Added alternative PDF download link

Version 1.3 (June 15, 2012)
Added PDF version for download for offline reading and printing

Version 1.2 (May 18, 2012)
Added photo of RAM w/ low-profile heatspreader (Thanks to our member Dawn1113 for the courtesy)
Added Cheapskate tip
Added preface to silicon acoustic lining (Thanks to our member dividebyzero)
Added Thermal Adhesive warning
Fixed malfunctioning link to Part-I

[FONT=arial]Version 1.1 (May 17, 2012)[/FONT]
[FONT=arial]Added link to IntelBurnTest[/FONT]
[FONT=arial]Thanks to our member slh28:[/FONT]
[FONT=arial]-Added links to reliable hardware review websites for components' specification verification[/FONT]​
[FONT=arial]-Added point about misleading manufacturer ratings[/FONT]​
[FONT=arial]-Added Fan Controllers section for Quiet Components[/FONT]​
[FONT=arial]-Added YouTube link on thermal paste application[/FONT]​
[FONT=arial]-Added partial exclusion for newer RAM modules[/FONT]​
[FONT=arial]Added to PSU, GPU, cases and water cooling kits to Quiet Component list[/FONT]
[FONT=arial]Added some cheap noise-reduction methods[/FONT]
[FONT=arial]Improved layout for better eligibility[/FONT]

[FONT=arial]Version 1.0 (May 16, 2012)[/FONT]
[FONT=arial]First publication[/FONT]


  • Effective Air Cooling Guide Part II.pdf
    432 KB · Views: 52


Posts: 709   +53
Major changes and additions done in both Part 1 & 2 on 17/5/12. More may come.
Thanks for the support, and enjoy!


Posts: 319   +71
Thanks for this, Marnomancer.

I actually did something you warn against here once. My CPU is a bit bigger than what I'd become used to, and so I was a tad overeager with the thermal paste. Had I not opened the case to clean out the filters a few weeks later, I would not have known that the paste had already oozed out from under the cooling block onto the motherboard. It was a mess. :D Had to clean it out very carefully and reapply the paste -- much less gusto the second time around. Good thing I didn't toast my CPU.


Posts: 4,840   +1,271
With regard sound dampening, silicone baking sheets can -with the use of a sharp blade and a template- be cut to any shape. It's what I use as the interface between watercooling radiators and fans, as well as harddrive bays. At a pinch you can also cut out rounds (silicone grommets/washers) using a short length of requisite diameter metal pipe (+ hammer and wooden block/bench), then use an office hole punch for cutting out the screw hole. Silicone baking sheets have an advantage of being available in many colours, will withstand any pressure (at least more than any component attached to it) without deforming, are usually 1-1.5mm thick -so won't affect clearances for screws, and are very cost effective. Here's a quick pic of a triple radiator gasket. The cut out middle section will be recycled for hdd/PSU dampening, and non-slip pads for chassis feet.


Posts: 709   +53
You always point out something that I hadn't noticed. :D
Thanks for that, DBZ. As long as it's cost effective, it's an excellent addition to the guide. Since this is more of a DIY, I'll add it to Part III. I might bother you later with a few questions on the how-to part.
Thanks again. :)


Posts: 126   +14
I like this guide as well as dividebyzero's guide about watercooling.. Thanks for posting those guides :)


Posts: 15   +0
Anything I can help with, let me know. :)

Great and thanks ! What do your ecommend the rear 140mm fan to be [exhaust or intake] on this pic with my CM V6 GT with the alternate install position.
Just a note that I seem to get a tighter mount with the cooler - better contact and pressure and less wiggle with this alternate CPU cooler install method. I also have the the 200mm side panel as intake and of course the top 200mm fan as exhaust.At the time I have the rear 140mm fan and top to be exhausting, since I previously had it mounted push - pulling front to back.

Just trying to better under the positive and negative air pressure in the above guide. Also would like to hear about some recommendations for improvements.

***Edit: One of the reasons I ask about this with fans too is because I may have seen the top fan as intake in some situations

Another note is that in this other pic link
I have the standard front to back and also an additional 120mm fan to supplement air circulation and it is not shown in the other pic.
Thanks for any support in advance.


Posts: 709   +53
I'm currently not near my PC, but I'll take a closer look at your pics when I get home.
A push-pull config isn't bad at all if it can keep the system at least 60% to the Tj.max.
Typically, the rear is an exhaust, as the power-supply's expelled hot air would go back in through it if it were an intake. That can be countered with a chimney as is now on my case's rear, but that spoils the looks.
The side panel as an intake with the bottom-front intake and top-rear exhaust is usually ideal in most cases, with CFM (filtered) deciding the pressure, +ve or -ve.
A top intake is (hypothetically) impractical, as most of the components which really need cooling are in the lower and rear-central part of the case, and providing the most direct airflow path gives the best cooling.


Posts: 709   +53
Not bad, pal. ;)
Your power supply is located at the bottom, so isn't an issue.
Setting a top-intake appears harmless in your case, provided it doesn't short-circuit the airflow. If you plan to make it intake in this case make sure to mount the intake at the front-top mount, not above the cooler shroud as in the pic. That way, the airflow should be something like this:
Top-2 Top-1​
| 111111111111v v v​
||<= |````````|<= // // //​
||<= | CPU |<=<<<​


Posts: 15   +0
hey @Marnomancer Thanks for explaining that and including the diagram, going to be moving that top fan to the front-top mount with the install of the front to back CPU cooler.Still think that it would be a good and modest investment to get another top fan and see about the alternate install with the cooler out the top.

Top-2 Top-1
| || || || || || ||
|| |^^^^^||
|| | CPU |
| |^^^^^|

Side intake, fronts intake, Rear exhaust, Top-1 intake ,Top-2 exhaust for this config link.
Thanks again for your advice and interesting discussion.


Posts: 15   +0
I apologize for attempting to get the diagram to look correctly in the above post..Being a newb around here may take a bit to get the hang of it.


Posts: 709   +53
Yeah, I know, the new "smart" post editor automatically removes blank spaces, becoming "oversmart", but I found a work-around: fill the gaps intended with dots/dashes and turn the text colour white. Haha.
I recommended the horizontal direction due to your GPU, whose hot air might get sucked in by your CPU cooler if set vertically. Another top fan would be counter productive, IMHO.
I'll finish Part 3 some time later, so you might as well read it up then and see what you can do. :)
Anything else I can help with, don't hesitate to let me know.



Posts: 15   +0
thanks for getting back and sort of chuckling to myself about the 'white out ' spacing fix for the "oversmart" post editor lol
anyhow actually did not think that the extra fan would do much ..and look forward to Part 3

thanks :)
Very well written guide! I've been building my own systems since the days of the 386 and have been working as a computer tech professionally for over 10 years, and in my opinion whether you have positive or negative case pressure, computers just build up dust way too quickly. :) I originally had my case set up using positive air pressure; I'm using an NZXT M59 case and it has bottom front and side mounted 120mm intake fans. This case uses a bottom mount for the PS and I'm using an Apevia that has 80mm and 120mm intake fans and an 80mm exhaust fan, which means it's drawing in air from underneath the case via the 120mm fan and from inside the case via one of the 80mm fans so in effect it is somewhat self-contained. It is pulling some air from within the case and exhausting it, but probably not to a great degree. The front and bottom fans are both filtered. At the back top of of the case is a 120mm exhaust fan, and on the top of the case I had two 120mm intake fans, so the intake CFM far exceeded the output (I'd estimate about a 2:1 ratio.) However, as you point out about "Intakes at the roof", this was not the ideal configuration and when I reversed these fans it made a huge difference in overall temp levels in the case - it dropped the average case temperature probably 10[FONT=Calibri]°[/FONT] C, but even more important it dropped my GPU temps from around 80[FONT=Calibri]° [/FONT]C under full load (Crysis 2) to 60[FONT=Calibri]° [FONT=Arial]C or so. The side mount fan pretty much blows directly on the top of the two video cards I have installed, but when I had the top case fans as intakes it was probably pulling back in some rising heat exhausting through the top and back grills (which are designed for either 120mm or 140mm fans - this particular case design has a LOT of open venting) and then most likely blowing heat from the CPU heatsink right back down into the video cards. It really does pay to play around with the configuration, and if I have to put up with a bit more dust, so be it. [/FONT][/FONT]




Posts: 709   +53
As long as you're benefiting (and your PC is chilling happily - both literally and figuratively), I'm glad to be of any help. :)


Posts: 19,282   +8,428
One of the biggest issues with cooling is the GPU itself. This for several reasons. The new long GPU boards divide a case in half. The active components on the circuit board are on the bottom, at the board prevents the normal tendency of heat to rise, effectively creating a puddle of hot air in the bottom of the case. Antec solves this in their 800 gaming case, (and I suppose others which I haven't examined), by supplying vented PCI expansion slot covers. You can actually aggravate this situation by not studying the airflow patterns induced by different capacity and velocity of airflow. In other words, every fan at peak output could conceivably inhibit some cooling potential.

Try not yo use all the HDD slots in a case. It'll cool much better if you use every other mounting slot. (Bigger drives for storage, and less of them).

I always use, a razor blade to spread thermal compound. The first coat, is always a skim coat on the CPU and heatsink, to fill up the pores. I had a great deal iof experience with a razor blade during my feckless youth, which means the suitability and success using this technique, may vary by individual...;)

I'm a bit puzzled with the singular recommendation of Scotch Brite pads as filters. The sizes necessary for use with larger fans, are really only available from pro auto body supply houses. (Feel free to correct me on that). Air conditioner foam should be suitable also, and it's "squishier", which should prevent you having to slice it to thickness. I have a CoolerMaster "Centurion" and that's what the stock filters are made from.

As to fans, bearing, and noise, my experience with interpreting the specs leads me to this conclusion. Fans marketed as "Quiet" most often push less air, by virtue of having their rotational speeds curtailed. The moral of the story is, if you want an honest 100CFM out of a 120mm fan, it's going to be fairly loud, period. This is what PCM fan control is all about. If you board has PCM ability, you should implement it by buying PCM capable fans.

As for passive heat sinks on add-in GPU cards, I doubt they would make the average gamer happy with their cooling performance.

At this point in space in time, the best defense against heat is, don't buy too much more performance than you actually need. Keep the overclocking to a minimum. That may require a step up from the cheap CPU you'd like to get away with, but it should "live longer". Base your next system on one of the i3 Ivy Bridge 2 core, 4 thread CPUs. (Main stream or home theater), At 55 watts TDP, you could practically leave the heatsink off. (Don't actually try that, I am, of course, hyperbolizing).

Still in all, if you could find an early Intel OEM heatsink, for example a unit from one of the Smithfield quads, that would keep an i3 Ivy pretty darn cool. (I've heard rumors that some of those early OEM coolers have copper cores). But no, you probably won't be able to overclock to 5Ghz with one of them.

And spring for round IDE cables, if you still need to use the IDE buss(s).


Posts: 709   +53
Brilliant post, Captain. Adding it to the appropriate sections of the guide ASAP.
As for the mention of Scotch Brite pads, I only wrote what I had actually tried or seen working. However, thanks for the information regardless.
About applying thermal paste with razor blades, it's something only the very experienced (say, like you, captaincraky) should do. It does take quite a bit of control to spread it out evenly.


Posts: 709   +53
Ciao amici!! :D
It's been a while.

I know ya'll were expecting Part III of the guide. Unfortunately the project has been delayed due to a number of reasons. I've been too occupied with my startup (we're making a new line of Linux PCs, with a complete OS, meant to match, if not exceed, the UX of a Mac. Other than that we offer mini-servers, web design, and app development). Then there's college. And health issues. AND an ever-changing PC environment, making it really hard to chalk out any working schematics.

So Part III of this series stands suspended as of now. Instead, I have something else on mind. What that will be, you'll see soon enough. ;)

Live long and prosper!