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CPU Running Curiously Hot

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January 3, 2007 9:33:14 AM

Hello Everyone

I've got a weird problem. I have just built two PCs with the following specs:

PC1
Intel Core 2 Duo E6600 (2.4ghz, Conroe)
Stock Intel Heatsink/Fan combo that comes with the processor
GIGABYTE GA-965P-DQ6
NZXT Adamas Case with stock fans (1 x 120mm rear fan, 1 x 120mm front fan, 2 x 120mm side fan)
Coolmax CUG-700B 700W Power Supply

PC2
Intel Pentium D 805 2.66GHz (Smithfield)
Aerocool Xfire heatsink/fan combo
GIGABYTE GA-8I945GZME-RH
NZXT Adamas Case with stock fans (1 x 120mm rear fan, 1 x 120mm front fan, 2 x 120mm side fan)
FSP Group (Fortron Source) ZEN FSP300-60GNF-R 300W Fanless Power Supply

When I power up PC1, the CPU quickly overheats and the computer shuts itself off. When I go into the BIOS and check the PC-health, I see the CPU temperature rise quickly from around 60 C to 100 C. When it reaches 100C the computer powers off - this takes about a minute. All the case fans appear to be running, as well as the CPU fan.
With PC2, the CPU hangs around a temperature of 85C, which is still very hot, but not hot enough to power off the computer.

I have not overclocked either of these computers. This is very puzzling to me since I am not putting the CPUs under heavy load, and I would think that my cooling, although nothing special or fantastic, should be adequate for these non-overclocked computers.

Am I simply not using powerful enough heatsink/fan combos? Or could there be another problem. If the solution is that I need a more powerful heatsink/fan, any recommendations for reasonably priced ones would be greatly appreciated. I do not intend to overclock either of these computers.

Thanks a lot!
January 3, 2007 9:52:27 AM

mpilchfamily - Thanks for your response

I did not apply any thermal paste to PC1 - since the stock heatsink/fan comes with thermal paste already on it. As far as I can tell the heatsink/fan is mounted properly onto the processor - all 4 pins are in securely. Is there anything else that I should check to insure that I have mounted it properly?

PC2 both the thermal paste and the mounting are slightly more questionable. I put a dot of thermal paste on the processor and then spread it over the entire surface using a Q-Tip. However, since then I have removed the heatsink and remounted it. Should I wipe off the thermal paste and then reapply it? This is the first time I have had to deal with thermal paste - all the other PCs I've built have not required any thermal paste. The mount pins that came with the heatsink/fan combo were quite bad and I am going to return this heatsink and get another one. But even so - this computer was the one that was running cooler of the two (although this may be because of the processor choice).
January 3, 2007 10:33:36 AM

Quote:
Any time you remove a cooler you much clean of the old thermal material and reapply it before mounting the cooler back. Otherwise you create air pockets in the paste that form hot spots. Also you never want to spread thermal paste with a q-tip. Follow the manufactures guide lines for applying the paste. If you can't find any then spread the paste in a thin layer using plactic wrap over your finger. Or you can use a credit card to get a nice smooth and even spread of it over the CPU. As long as the cooler is nice and flat and apears to be set all the way on the CPU then you should be OK.

Do you have any other cooling in the cases?


Thanks for this suggestion regarding the thermal paste. Should I try taking off the heatsink/fan on PC1, wiping off the thermal paste, and reapplying it? Also, is a papertowel a good way of cleaning this off?

The cases have 4 120mm fans, two on the side, one on the front, and one in the back. The one in the back is very close to the CPU, and in PC2 it seems like its effectiveness would be hampered because the HSF is very large and partially blocks it. Even so, I would think the other 3 case fans would provide adequate ventilation, but perhaps not. The chipset on both PCs simply has a heatsink placed over it - this is how the motherboard arrived. The graphics cards also have small fans on them (WinFast PX6200TD in both). PC1 has a fan in the powersupply, and PC2 uses a fanless power supply. Other than that, there are no additional cooling devices.

Something I forgot to mention on my first post was that I had PC1 on for a good 5 minutes or so when I first built it (not doing anything, simply idling). I then hit the restart button and from that point forward the computer would not stay on for more than a minute or two. Perhaps there was some weird fluke here - I don't know. Is it possible that the thermometer on the motherboard is ineffective or reporting false values? It seems like a longshot - but I can't understand why I am having these overheating issues in the first place.
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January 3, 2007 11:32:30 AM

A bucket of ice and cold water should solve that problem. No really. Try remounting that cooler and with good thin layer of thermal paste between the cpu and cooler.
January 3, 2007 11:57:45 PM

Thanks for the suggestions - I will try these things

There's one more thing that I realized might be affecting this. PC1 has the 20 or 24 pin ATX option, and then rather than a 4 pin 'additional ATX power' (i don't remember the technical term for this), it has 6 pins. I had the option of using 4 or 8 pins, so I opted for the 8. I also opted to use the 24 pin ATX instead of 20. I would guess that the extra 4 pins would simply be a source for greater voltage/an extra ground if the processor required it - but could it be that it is placing too great of a voltage across the processor and that's why it is overheating?
PC2 has 20 or 24 pin ATX option, plus the 4 pin additional ATX power - so I plugged in the 24 pin as well as the 4 pin. Perhaps the same thing is happening here? Could using the 20 pin (instead of 24 pin) + 4 pin additional ATX power fix this?

Thanks again
January 5, 2007 1:07:10 PM

Well, I've fixed it. Turns out the problem was that the HSF wasn't making proper thermal contact, but it took removing both mobos to see it =/. The stock intel HSF that comes with socket 775 processors is terribly annoying to install properly - because you can install it in such a way that it looks like you've done it correctly, but it's not right at all. More detail in my post here: http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1431908#1431908.

Thanks to everyone for their suggestions and help with this issue :) 
January 6, 2007 4:15:24 AM

I just wanted to add something regarding thermal paste and such. Firstly, I'd always recommend using Arctic Silver 5 as it's simply one of if not the best out there.

Whenever you take off the heatsink and put it back you must take off all the old thermal paste and apply new. I like to wipe off the old with a soft, lint-free cloth. This next part is important, take a cotton ball (or something like) and dip it into isopropyl alcohol (rubbing alcohol) and clean off the CPU and heatsink with this. Alcohol will ensure it is cleared of all remaining debris and best of all it will just evaporate when it's done. I then put a pea sized dot of thermal paste onto the CPU and just mount the heatsink on it and let the weight and pressure of the heatsink spread it out for me. This is how they recommend doing it on Arctic Silver 5 website. With this method I run at a cool 32C idle.
January 6, 2007 4:25:10 AM

I can testify to the fact that squirting a bunch on and spreading it out with you finger is NOT the way to do it. That's what I did the first time I put my phancy schmancy new Infinity on my e6700. Couldn't figure out why it wasn't running any cooler than the stock HSF. Did some reading around here and re-installed using the credit card to spread an even, thin layer. After a thorough cleaning of all the goo I had left last time. When I took it off to re-install, it was an ugly mess. Runs cooler now.

Tom
!