TechSpot

Help with Cooling / Fan Speed

By expatcdn
Jun 21, 2007
  1. I know my way around computers, but I'm new to the issue of cooling.

    I'm running a P4 2.93 GHz on an Intel D945PSN motherboard. Until two days ago, my cooling "system" consisted of the PSU and the heatsink/fan that came with the CPU.

    Within the past week, I started to receive warnings that the temperature was a bit high (60-63C). I have since installed a Silverstone FN121 120mm case fan directly below the PSU. With this new fan, the temperature dropped by no more than 2-3C.

    I went into TigerDirect and talked to a fellow there who strongly suggested replacing the stock heatsink/fan with a better model. I have now installed a Cooler Master Hyper TX.

    The difference in sound is unbelievable, but the temperature is still a bit too high (I think) and I'm getting warnings from time to time that the fan is either stopped or very slow.

    While using the computer (although, not under 'full load' conditions), the temperature has stayed around 58-60C and the fan has been about 300 RPM. At approaching a 'full load', the temperature was 63-65C and the fan was around 1300RPM. Right now, with the computer virtually idle except for my having VNC'd in from work, the temperature is 52C and the fan is at 100RPM.

    I have no knowledge of this, but I'm assuming that the fan works as fast as it thinks it needs to get to the desired temperature. So, should I be concerned about the fan speed? If no, does that mean the temperature is actually ok?

    I think I'm going to add an 80mm intake fan on the front of the case but, since the 120mm fan didn't make much difference, I'm not sure how much an 80mm will help. Still, I keep getting these warnings and I'm not sure what to do next.

    Any suggestions will be gratefully received.
     
  2. Billy213

    Billy213 TS Rookie Posts: 59

    With heatsinks they run the speed they need to:

    Cooler CPU = Lower RPM
    Hotter CPU = Higher RPM

    I don't know much about the different temps for different CPU's but in general yours does seem a bit hot (might be wrong), seeing as you have upgraded the heatsink as well.

    It's always good to have good airflow within the case as this will help keep all the other components at a lower temperature. I'm not sure about an front intake of 80mm helping to cool your CPU but it mite be an idea for the hard drives etc.
     
  3. expatcdn

    expatcdn TS Rookie Topic Starter

    I have now installed an 80mm fan on the side of the case with no appreciable results. I have also downloaded and installed SpeedFan to double check the readings that the Intel software was providing. They match. Temperatures are around 56C but the CPU fan is at 0. Only once I break 60C does the CPU fan start up and even then, it's only ~300RPM.

    I was just wondering... is it possible that I did not seat the heatsink properly? Could that be my problem?
     
  4. Billy213

    Billy213 TS Rookie Posts: 59

    So you mean at one point the heatsink fan wasn't even spinning?
     
  5. expatcdn

    expatcdn TS Rookie Topic Starter

    Yes, exactly. I just VNC'd into my home computer and SpeedFan is reporting the temperature to be 54C. While the 120mm and 80mm case fans are running normally (1293 and 2157 RPM), the CPU heatsink/fan is sitting at 0 RPM. I know that it is at least connected properly, because if I were to start putting a normal load on the CPU, the temperature would rise to ~63C and the heatsink/fan would start up to around 300 RPM.

    This is what got me wondering if maybe the heatsink isn't making proper contact with the CPU. I am just about to run back out to TigerDirect and acquire some thermal paste. When I get home, my plan is to take the heatsink/fan off and re-install it.

    Does that make sense?
     
  6. Billy213

    Billy213 TS Rookie Posts: 59

    Yeah i can see what your saying now. Maybe reconnecting the cable that links to the motherboard would help? just a thought...i've never heard of anything like this before lol.
     
  7. CCT

    CCT TS Evangelist Posts: 3,556

  8. expatcdn

    expatcdn TS Rookie Topic Starter

    OK, so I've re-installed the heatsink/fan along with a healthy coat of thermal paste. The temperature is holding steady at 52C -- it actually got down to a record low of 48C!! -- but the fan is running at only ~130 RPM, so I'm continuing to get warnings from the Intel software.

    At full load, the temperature was reported at 57C and still the fan was at only 130 RPM.

    [​IMG]

    CCT, thanks for posting the link to Intel. I'm in the process of going down the list to see if I can isolate the problem. However, the only warnings I'm getting right now are about the fan speed and, I think, if I can get the fan running properly, the temperature would probably drop.
     
  9. RoLeRzzz

    RoLeRzzz TS Rookie

    try to disable PWM or automatic fan speed settings in BIOS. now your fan should go at full RPMs. If it dont help just plug it's power cord into different fan feeding slot on motherboard.
     
  10. Bienb

    Bienb TS Rookie

    Intel's new motherboard BIOS were designed by arrogant jello for brains engineers. They did away with users' choice of lowering the temperature switch setting for full fan speed. The only logic I can gather is that they assume everyone uses their computers in very cold airconditioned rooms.

    There is no getting around this problem unless you want to connect your CPU fan directly to your 12v power line and do away with automatic control. At least you'll get the CPU running as cool as possible with full fan speed.

    Intel emailed me that they will "consider" adding lower settings to their fan control in future BIOS updates. "Consider"? As if running the CPU at low temperatures is a bad thing.

    My cheaper MSI motherboard runs cooler and faster than my Intel mobo purchases. My advice? Avoid Intel motherboards until they get their heads on straight.
     
  11. almcneil

    almcneil TS Guru Posts: 1,554

    Yep, I had this problem with my step-father's computer. It's not the CPU or PSU fans, it's that the inside chamber is not venting the hot air, so it builds up and you get warnings that the temps are too high.

    What you need is a "system" fan. Most MoBos come with a spare outlet for a secondary "system" fan. This fan is installed at the inside uper vent on the chassis. It's purpose is to evacuate the hot air from the chamber (or chassis) so it doesn't build up. Installed the system fan on my step father's comp and it worked like a charm! His warning and shutdowns from high temps disappeared and the temps are steady in the high 30s, low 40s.

    BTW, uninstall that higher speed fan. I did the same on my step-father's comp. We first installed a faster fan but it made little difference and was NOISY!! I put the old one back in and then installed the system fan and it worked like a charm. Noise is low and the temps are fine!
     
     
  12. Daveskater

    Daveskater Banned Posts: 2,031

    when you reinstalled the heatsink, how much thermal paste did you use? you're just supposed to put a thins layer on because otherwise the heat won't get through the paste

    also when you put a fan in the side of the case, is the air blowing in or out? if the fan points in the general direction of the cpu then make sure it brings air into the case instead of venting it out because it will bring cold air in from outside the case and blow it straight onto your cpu

    i did an experiment with my case fans (i have one on the sie and one on the top of the case) and when i turned the fan on the top over so it brought air out of the case, then temps dropped dramatically inside the pc. also when i turned the fan on the side of the case round the inside temp went down a tiny bit but the cpu temp went up as well

    try connecting the fan to one of the other fan connectors on the board though because it should run it at full speed all the time then and you can see what it's really capable of ;)
     
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