High CPU temperature during idle

tommedema

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Hello,

I'm running the following desktop box:

Motherboard: Gigabyte GA-P35-DS3L
CPU: Intel Core 2 Quad Q9550,Boxed, Q9550, Socket 775
Video card: Asus Radeon HD4870,GDDR5, PCI Express x16, 512MB
Memory: 8GB DDR2 (Kingston KVR667D2N5/2G, 2048 MB, DDR2, PC5300, 667 MHz x 4)
Box: Cooler Master CM 690
Power Supply: Cooler Master Real Power M620,Retail, 620Watt

I looked into my BIOS, which has all default values set by Gigabyte:

HDD S.M.A.R.T. Capability (Disabled)
Limit CPUID Max. to 3 (Disabled)
No-Execute Memory Protect (Enabled)
CPU Enhanced Halt (C1E) (Enabled)
CPU Thermal Monitor 2 (TM2) (Enabled)
Virtualization Technology (Enabled)

SATA AHCI Mode (Disabled)
SATA Port0-1 Native Mode (Disabled)

ACPI Suspend Type (S3(STR))
Soft-Off by PWR
HPET Support (Enabled)
HPET Mode (32-bit mode)

CPU Smart FAN Control (Enabled)
CPU Smart FAN Mode (Auto)

Robust Graphics Booster (Auto)
CPU Clock Ratio (6X)
Fine CPU Clock Ratio (+0.5)
CPU Frequency (2.16Ghz, 333x6.5)
CPU Host Clock Control (Disabled)
CPU Host Frequency (333)
PCI Express Frequency (Auto)
C.I.A.2 (Disabled)
Performance Enhance (Turbo)
System Memory Multiplier (SPD) (Auto)
Memory Frequency (667)

System voltage control (manual)
DDR2 overvoltage control (Normal)
PCI-E OverVoltage Control (Normal)
FSB OverVoltage Control (Normal)
(G)MCH OverVoltage Control (Normal)
CPU Voltage Control (Normal)
Normal CPU Vcore (1.02500V)

Now, here is the problem. In BIOS, my CPU temperature is 84 degrees celcius. System temperature is 41 degrees celcius. When I login to windows 7 and use CoreTemp, I see that all 4 cores are at about 55 degrees celcius, where the highest value is 66 degrees celcius. Notice that this is with casual browsing, I am not running arithmetic heavy applications whatsoever.

Why would my CPU be so hot while my PC is idle, and why so much hotter (84 degrees) in the BIOS?

I think I have positive air pressure in my box, there is 1 fan sucking air in at the front. The bottom power supply has a fan at the bottom. Then there are two fans sucking air out, one at the top of the back and one at the rear end of the top of the case.

Note I am a newbie to these things. I have no idea what these BIOS settings mean nor if they are setup correctly.

Could anyone help me with my temperature issue and/or inform me of any possibly "stupid" BIOS settings?

Thanks a lot.

Kind Regards,
Tom
 

tommedema

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Now that I think of it it might be that the old thermal paste that was on the CPU / Heatsink was removed. May this be the cause?
 

tommedema

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I'm not allowed to edit messages.

I just tried it again in the BIOS. Temperature started at 38 degrees and rised steadily to 75+ degrees.
 

pocketdexter

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Thermal paste must be applied to the cpu if the old paste was removed. The paste helps transfer heat from the cpu to the heatsink by covering the small imperfections in the heatsink. No paste will definitely make the cpu overheat, thus creating a hard system shut down to prevent damage. Make sure to install a small amount of paste then reseat the heatsink on to the cpu.

Next thing would be to clean up your case and components with compressed air. Lastly, what is the ambient air temp because this will factor in to how much cooling your fans can achieve.

Your cpu can handle up to 71.4C temps (anything higher is definitely going to shorten its lifespan or cause premature failure).
 

tommedema

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Oh, that is very worrying news.. 71.4C? It has been at 84C+ already.

The strange thing is that it never crashed. I have just ordered this thermal paste:

http://www.amazon.de/gp/product/B0045JCFLY

You said I have to put only a bit of paste on the CPU / heatsink, is it bad if I put too much on it? I have no idea how much is good or not.

Thank you.
 

pocketdexter

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here is a video showing how to apply thermal paste on intel and amd cpu's
http://www.youtube.com/watch?v=fRRWbQUqW1Y&NR=1

The good thing about the mx-4 paste is that it is not conductive meaning that if you put too much you won't short anything. As long as the paste doesn't leak to the sides of the cpu when you install the heatsink then you will be ok. The whole cpu doesn't need to be covered.
 

tommedema

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Thanks, I put the paste on there and now the temperature is about 45 to 55 degrees. This is fine, right?

I do think I put more paste on there than necessary, but not problems so far...

Thanks again!

 

pocketdexter

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Anything below 71.4C is acceptable
 

tommedema

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Alright. By the way, that's quite a curious number, 71.4. Mind if I ask why 71.4 precisely? In other words, why would 71.3 cause no harm while 71.5 would? Sounds very interesting although somewhat awkward. :)

Thanks!
 

pocketdexter

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According to the datasheet for your yorkfield cpu, the maximum operating temperature for the chip is 71.4C. It can handle temperatures up to that point safely. Anything more and it is overheating. Obviously less temp is always better especially if you ever want to overclock :)