Core Temp vs. Chip Temp

[Srotten]

Hi all,

I'm trying to understand the difference and limits of core temps vs. the overall chip temp. My core temps on my Q9450 (quad) are all in the high 50c to low 60c yet my overall chip temp on HW Monitor and in the BIOS is around 38c or lower.

I know Intel has a "high thermal limit" on the chip recommended at 70c, but is that for the chip itself or for each core? If for whole chip, what kind of core temps should be alarming vs. regular.

Also, how can the cores be running so hot yet the overall chip stays cool (other than probe placement). Are hot cores and a cool chip a sign of good a good heat sink? Or is it a bad heat sink because it's not cooling the cores themselves.

Any help with this is much appreciated.

-Mark

 

[krnmastersgt]

How exactly are you checking the BIOS temps at full load? Anyways go with the temps you see on the cores, the overall temp of chip doesn't really matter all too much.

 

[Srotten]

Using HW Monitor and Core Temp (also checking chip temp in the BIOS by rebooting ASAP)... as for load, just running Prime95 or gaming or whatever to put some stress on the system.

So is 70c the max for Core Temperatures?

 

[krnmastersgt]

I believe thats the number people try not to pass for Yorkies, and the temps are going to be vastly different if you reboot to check the BIOS temps than if you're checking while stress testing, so that isn't really an effective gauge on temps.

 

[Srotten]

OK...

Lets just drop the whole BIOS question and get back to the original post (eventhough the BIOS Temp and the CPUSYS temp from HW Montitor basically said the same thing using my ASAP method).

What is the maximum thermal limit of the cores instead of the chip as a whole?

 

[krnmastersgt]

70C is the temp you don't want to pass. Most shoot to keep it around 60-65C.

 

[Srotten]

Can anyone answer my other questions as to why there is such a big difference between core and chip temperatures?

Seems to me if I have 4 cores running 60c, they should heat the overall chip up to around that temp as well.

Anyone else seeing temps like this?

-Mark

 

[rge]

Cpu temp (from diode between cores) and Core temp (diode on die) should read nearly the same at idle, and at load core temp may be ~5c more than cpu temp, depending on the load. But that assumes you have accurate sensors, and the following:

1) For accurate CORE LOAD TEMPS, you use the correct tjmax of 95 (and not 105 tjmax which is default of coretemp/HWM for 45nm which will make load core temps read 10C too high)
2) For accurate CORE IDLE TEMPS, either calibrate them with Realtemp or ignore them as they are nonlinear and tend to read too high until reaching load temps, ie delta to tjmax of 25-35 or less.

3) For accurate CPU temps, your bios manufacturer must have calibrated properly for your cpu, if not it may be inaccurate, also assumes you have the latest bios.

Intel will state that the specs refer to the CPU diode. But since load Core temps are calibrated at the factory by intel and more accurate AT LOAD than anything else, and since the gradient from core to cpu is between 0 and 5C, most apply the same specs to Core temps, including myself. That gives you a few C additional safety margin, and more accurate temps (load core temps calibrated by intel and independent of bios error) unlike cpu temps.

BTW...helps if you state whether temps measured at load or idle.

 

[Srotten]

THANKS rge!

That was exactly the kind of help I was looking for. My opinion was that those temps had to be wrong for that big of a difference and the 10c that you mention would put everything about in line. I couldn't figure it out because nothing in the system was excessivly hot, yet I was getting those kind of readings.

BTW that was at a typical load level gaming or running Prime95.

I do have the latest Bios, and I'll download Realtemp and calibrate it correctly.

Quick question... my GTX 280 Gfx card is showing a peak core temp of 71c after gaming(no overclocking) does it have the same error in HW Monitor? Is it ok for it to actually get that hot? It is like a toaster so I believe that temp is accurate.

Thanks again for the explaination, I like to understand what is happening and your explaination makes sense!

-Mark

 

[PlasmaBomb]

I'm not aware of any errors on Nvidias part... GPUs get toasty...