Simple overclocking FAQ

I'm not sure if there ever was an Overclock FAQ on the forums itself. Given that there is a good number of threads asking for overclocking advice on the forums, and that most of them come to similar conclusions, I think I'll just put this thread up.

Introduction:
This overclocking guide is written NOT to give a step by step instructions on how to push your computer as far as possible. It is written to give people out there some basics on overclocking. This includes the 5 Ws and the H (Where, When, Why, What, Who, How). In fact, it'll be titled such (the How section will be the longest, probably. Because its my last name ). I will also provide links
to some other guides which may be of more help once you're past this.

The other thing I'd like to bring about with this guide is the dangers involved with overclocking. Its a good thing going on here at Techspot, where threads asking for overclocking help will almost definately get a reply about the dangers.

WHAT is overclocking?

dictionary.com said:

overclock:

/oh'vr-klok'/ vt. To operate a CPU or other digital logic device at a rate higher than it was designed for, under the assumption that the manufacturer put some slop into the specification to account for manufacturing tolerances. Overclocking something can result in intermittent crashes, and can even burn things out, since power dissipation is directly proportional to clock frequency. People who make a hobby of this are sometimes called "overclockers"; they are thrilled that they can run their 450MHz CPU at 500MHz, even though they can only tell the difference by running a benchmark program.

Click to expand...

Overclocking would involve the CPU, RAM and graphics card at the moment. God save us the day HDDs become overclockable. Interestingly, optical drives are "overclockable", but it is strictly limited to very old, ROM only drives which run at X8 or thereabouts. I won't go into that at all.

WHO should overclock?
People who know their computers well enough to troubleshoot problems that come out, AND able to pay for and install damaged components.

I wouldn't recommend overclocking to anyone who has not built a computer from parts, or requires help to install a new component. You will also need to be familliar with the BIOS.

WHO should not overclock?
People using laptops.

Laptops are generally designed with very minimal tolerances, and an increase in temperature brought on by overclocking will most likely step over these tolerances and bring about stability issues. Therefore, even if you tried overclocking a laptop, you wouldn't go very far.

This of course doesn't apply to a desktop running laptop parts.

WHY should I overclock?
If a computer is running sluggish on new games, overclocking may improve performance quite enough to make those games playable.

Overclocking can also be done to get the performance of a budget computer up to the performance of the top of the line computer.

Overclocking is also a great way of learning more about computers. This however, varies from person to person, and for me, my overclocking experience gave me a much better understanding of how the computer works, after stuffing up the overclock many many times... (Oh, the error messages!!)

WHEN should I overclock?
There's no real when you should overclock. Given the dangers, the only time a total newbie should try overclocking would be on a computer they're going to dispose of.

Or if you already know your way around a little, when that new title comes out which plays like a slideshow.

WHERE should I overclock?
It depends solely on how you're going to do it. If its gonna be done under liquid nitrogen cooling, I'd suggest in the middle of a football field. Most of the time it'll be in your room/office/wherever your comp usually is. Be aware that there may be a need to open the covers during the overclocking, so some space is good.

HOW do I overclock?

This is the fun part, isn't it?

I'm going to do something really really basic here.


CPU Overclocking:
First, you restart your computer. Right at the start, there should be a line "Please press <something> to enter BIOS/setup/settings/something like that". Press that something. Its usually Del, or one of the F function keys.

You will then be transported into the BIOS. Its usually nice and blue, and might look like this
http://img.photobucket.com/albums/v288/UncleBob1/VNF4ULTRA/BIOS Screens/VNF4ULTRABIOS1.jpg

You will then have to look for some sort of Frequency/Voltage control. Given that different motherboard makers use different BIOSes, finding this may be a problem. But what comes out should be similar to this:
http://img.photobucket.com/albums/v288/UncleBob1/VNF4ULTRA/BIOS Screens/VNF4ULTRABIOS26.jpg

From there, you're supposed to increase the Front Side Bus (FSB) <This is known as Baseclock (BCLK), or maybe even QPI, in the Core i7>. In the photo above, its just put as a simple "CPU Frequency". The default number varies depending on the CPU you're running. How much of an increase you should make would depend on how much of an overclock you're trying to acheive. How much can be acheived would differ greatly between different makes of CPU. For example, CPU A might be able to reach a 70% overclock, while CPU B may only reach 20% overclock. Even then, different chips of the same CPU will overclock differently. My friend's CPU A might reach 80% overclock, while my CPU A may only reach 60% on the same hardware.

Once the FSB is changed, you save and exit the BIOS. THERE! Your computer has been overclocked.

The fact that it starts up or not is quite irrelevent. Your CPU is now running at overclocked speeds.


Now, to make sure your computer starts up.

First, you can try doing less of an overclock. The general idea is make small increments on your FSB, instead of a large increment. Increasing your FSB by 10 each time is a good way to start. Each time you increase this, see if your computer boots up, and play your favourite game for a few minutes. If it can do that, restart and increase that FSB again. Repeat until it will not play your favourite game. Once it cannot, go back to the last FSB, and leave it there.

Seasoned overclockers will test for stability by running a program that'll stress the computer. Prime95 is a favourite, but there's many different programs out there that does just about the same thing.
https://www.techspot.com/downloads/5679-prime95.html

You can run the program for 15 mins to see if you're system's stable before going on a higher FSB. Before settling on a particular overclock, run the program overnight to see if its truly stable. If not, reduce the FSB again.

Of course, if it runs your favourite program while you're playing it, its stable enough for your own use.

Troubleshooting:
If by some luck you increased your FSFB so much that your computer wouldn't even go to BIOS after resetting it, you will have to clear your CMOS. To do this, open up the left cover of your computer (assuming a basic tower style case). On the motherboard (you know what that is right?) there should be a flat-type battery (usually a CR-2032). Remove the battery, and wait for a minute. Replace the battery. Your CMOS should be cleared. Inserting a similar sized coin to the battery into the battery holder helps (and you won't need to wait that minute).

Note: Some motherboards these days allow CMOS clearing without the removal of that battery. In these motherboards, you can follow the instructions given in the motherboard manual, but following these instructions should still work. If you're unsure, and cannot locate your motherboard manual, just remove that battery as above.


GPU Overclocking:
GPU overclocking is harder, and easier at the same time. Harder because you cannot use BIOS to do it, easier because there's software out there which can do it. However with software, it will not support all cards.

A good software would be the ATITool. Despite its name, it supports nVidia cards as well. (may be outdated, look for updated versions)

https://www.techspot.com/downloads/447-atitool.html
<Windows 2000/XP/2003 (both 32 & 64 bit) only>

Simple enough to use, just take the Core or Memory slider and bump it up some. Then scan for artifacts. If you don't see anything abnormal (also known as artifacts), keep bumping it up. Same as CPU, keep bumping it up until it starts showing artifacts. Artifacts are random stuff that appears on your screen, it may be dots, lines or shapes. The program may pick these up and tell you about it, but I know that it doesn't pick up all artifacts, so keep an eye out while scanning. Once you find the highest clock for both Core and Memory, click on New, give it a name, and Save.

Now, when you need that graphics card to perform, open ATITool, and load up your last configuration.

Continued...

HOW can I get a better overclock?
Better quality parts
Generally, getting a better motherboard, and better RAM will give you better overclocks if you overclock in the method outlined above. You generally get what you pay for, so don't expect your budget $50 motherboard and generic RAM to give you good overclocks. Then again, there will be some overpriced motherboards and/or RAM out there, so some research before investing in your hardware would pay off.

Better cooling
If you have already bought all that, getting better cooling will also generally give you a better overclock. This may be something as simple as adding more fans on your case, or changing the heatsink/fan on your CPU/GPU or Northbridge, but I don't recommending messing with the northbridge because the gains are usually minimal.

Thermal pastes
There is also something called thermal compound/paste which will help tremendously with cooling. Thermal compounds basically bridge the gap between your chip and the heatsink. Air is a very poor conductor of heat, and is the stuff that stays around these gaps, making your heatsink less efficient in trasferring heat away from your chips. Given that both the chip surface and your heatsink surface is pretty flat, there's not much of a gap there. Therefore, you don't need alot of it to be effective. Almost all the time, a half-grain of rice sized portion of thermal paste is enough. More will usually be worse than too little in this case.

The cheapest thermal compounds you can get are probably the ceramic thermal compounds at your local electronics shop. Most heatsinks come with their own packet of thermal compound, or already has thermal compound packaged with the heatsink, so you don't need to buy some. If you got your computer installed for you at a computer shop, it probably has it already.

However, if you're after high quality thermal compound, Arctic Silver 5 is the thing thats being worshipped by overclockers around the globe. I don't think there's any other thermal compound as effective (and definately as well known) than AS5. There are some review sites that reported compounds that perform better than AS5, but given that I can't find any other site reproducing the results, I'll probably stick with AS5.

WHY should I not overclock?
The obvious reason is because there is a chance your computer will not work after that.

Stability
Overclocking should not be done if you require 100% system stability. Even after stability testing on an overclock, you can not be certain that you will get 100% stability. I don't know when an average user that would refer to this guide will ever need 100% stability, but I'd point it out anyway. After extensive stability testing, there is still that odd chance your computer will crash. My comp runs at a 25% overclock 24/7, and crashes once a month under very specific circumstances. (e.g. 80% CPU load for over 48 hours)(new computer at over 40% overclock does not have this problem, thank god). I will also note that it gets really hard to determine the cause of crashes once you overclock.

Lifespan
Overclocking is supposed to reduce the lifespan of your computer system. Computers are like cars: they break down with use. And with overclocking, you accelerate this process. How long you would expect an overclocked system to run is very subjective, and rumors go from 1 month to 15 years. Don't overclock if you cannot afford to replace your comp.

I'm not going to explain the physics behind why overclocking reduces the lifespan of the computer, but heat is a contributing factor. A contributing factor means its not the only thing that causes your computer to malfunction. Even if you took appropriate steps to keep temps low, eventually your computer will still break down, and at a faster rate than if you didn't overclock. This is especially true if you change the voltages (which I will NOT cover in this guide).

Also note that CPUs last for many many years, far more than its useful lifespan. Halving its lifespan will still allow you to use your computer until you desperately need to upgrade it. And more. Chances are good that just about everything else dies out first (motherboard, HDDs, DVDRW, PSU, fans, etc)

Maintenance
Upgrading your computer may also prove to be difficult with overclocking, as your new part may not work well with an overclocked computer. This is especially true if you're adding RAM (new RAM won't work at higher speeds), or it may be a PCI card (sound card, RAID controller, etc). There are also reports of HDDs malfunctioning because of FSB changes, newer motherboards probably won't run into this problem.

HOW does overclocking work?
This can get VERY heavy... Each CPU has its own multiplier, and this value is multiplied by the FSB speed, to give you your CPU speed. So the formula for your CPU speed would be: CPU multiplier x FSB. No matter what multiplier your CPU is at, or the FSB for your system is, if these come up to the same value, it'll perform roughly the same. I'm oversimplifying this, because there are differences, but given that most users wouldn't be able to change the multiplier, these differences wouldn't matter. This guide assumes the inability to change this multiplier, and therefore focuses on changing the FSB.

Circuitry wise...
You'll have to see how CPU makers make their chips. No, they do not have a different fabrication process for the different speeds of the same family of chips. Therefore, when you receive a Core2Duo E6600, its from the same batch of chips some E6700, X6800, E6400, E6300 come from. They differentiate this through testing after these chips are produced. These tests determine how much imperfections there are in each individual chip. From this testing, they decide that one chip may perform at X ghz, while another will perform at only Y ghz, and they sell them accordingly. You will also realise that the different speed chips perform at different voltages as well. The faster chips will require a higher voltage.

Now you might ask why you shouldn't increase the voltage of your low end chip. The imperfections in each chip mentioned earlier cause problems such as overheating when given more voltage. Which is why manufacturers won't sell it to you at the faster speed in the first place.

Anyway, its because all chips are different that overclocking is possible, and that each chip will produce different results. Low end chips generally overclock better as well, because the theoretical maximum chip speed is the same throughout the whole family of chips (therefore, your E6300 and the X6800 should be able to perform at the same maximum speed, if they both had no imperfections).

Also, CPUs react to 1s and 0s. 1 is "high voltage", 0 is "low voltage" basically. The faster your CPU runs, the "harder" it is for the CPU to differentiate between the 2, giving errors. This is why giving a higher voltage help give a higher overclock, the extra voltage makes the voltage difference between a 1 and 0 much larger. Of course, just like how putting 20V through a 12V lamp burns it out, putting extra voltage through your CPU burns it out as well. You may not see it burning visibly, but overvolting it runs the risk of destroying delicate circuitry within the chip itself. "What if you freeze the CPU first?" you may ask. You're still limited by how fast that heat can be transferred out from that particular part of the chip. Chances are, it'd burn out before you'd even notice any change in the CPU temperature.

This section has been oversimplified. I'm sure some electrical engineering textbooks will have more details if anyone's interested. Given that I am not an electrical engineer, and that this is secondhand information from one who works in a chip fabrication plant, I believe it is true. Pls correct me IF there are major mistakes. Or things to add.

Disclaimer:
I didn't write this guide. It magically appeared. You didn't read it. Techspot didn't write it. Techspot doesn't endorse it. In fact, you wrote it.

If you don't agree that you wrote this guide for your own use, do not follow this guide.

If you agree that you wrote this guide for your own use, and your computer doesn't work after following this guide, its your fault.

End Notes:
Like I said, this is supposed to be a very simple guide to overclocking. There are many ways to get to the highest possible overclock, this is NOT one of them. Higher overclocks may be acheived by increasing the voltage for your CPU/RAM/NB/GPU, relaxing RAM timings, changing speed ratios, etc. Applying higher voltage significantly reduces computer lifespan, but result in higher gains. Most other ways of acheiving higher overclocks not covered in this guide will give minimal returns, and not worth bothering unless you're really serious into overclocking.

Useful link:
Overclocking software: http://www.hardforum.com/showthread.php?t=962154
Techspot user's CPU temps: https://www.techspot.com/vb/topic73469.html
Max CPU temps/Voltages: http://users.erols.com/chare/elec.htm
Stability check: http://www.mersenne.org/freesoft/
CPU temp monitoring software: http://www.alcpu.com/CoreTemp/

I hope this brings up some discussion about simple ways to overclock.

07/03/01 Added section on how overclocking works. Added CMOS clearing.
07/03/15 Added reason not to overclock. Clarified points on "how overclocking works". Added section on thermal paste under "how can I get a better overclock".
07/03/20 Added "overclocking software link".
07/04/17 Added Link to CPU temps and max CPU/voltages.
08/04/07 Updated mention of new computer's stability. Included subtopics.
10/01/21 Added section "who should not overclock".
10/02/27 Added BCLK, which is the new FSB.
10/06/15 Added 2 links. Added paragraph in "lifespan". Updated ATITools.

CMH said:

Disclaimer:
I didn't write this guide. It magically appeared. You didn't read it. Techspot didn't write it. Techspot doesn't endorse it. In fact, you wrote it.

If you don't agree that you wrote this guide for your own use, do not follow this guide.

If you agree that you wrote this guide for your own use, and your computer doesn't work after following this guide, its your fault.

Click to expand...

That has got to be the best disclaimer ever It gets the message across humorously and quickly unlike the usual 150pg novels included in some small piece of Micro$oft software *coughMSNcough*

STICKY????? I THINK SO!


BTW I think this guide is great. Mostly because it is clear, and partly because it doesn't explain voltages, reducing the risk that newbies will cook their CPUs by putting a 1.4V CPU at 3V or something along those lines.