Low idle temp on Athlon 640

[anoa]

Just put together a new system that included an Athlon II X4 640 and a Asus M4A785TD-M EVO. I am noticing very low idle temps. Using CPUID Hardware Monitor I am getting core temps around 12C with motherboard temp of 34 and what I believe they call the socket temp of 28. The ambient temp in the room is around 21C. The system is running the stock cooler as well.

I have been running Prime95 for about fifteen minutes now and the temps are up to 38 at the cores, 40 motherboard, 48 socket. The cpu fan has gone from 2100 to 3170 and the case fan as gone from 630 to 1130.

Do these temps sound right? The idle temp at the cores sound very low, since they are below ambient. Then they also seem low while running Prime95. The other two temps seem about right. Is there a known issue with this CPU that might report low temps?

I have also used Speedfan and CoreTemp and they are showing the same temps.

thanks

 

[Herr_Koos]

The 12C does not seem correct, but all the other temps are fantastic. Can you perhaps post a screenshot from CPUID HWmonitor? Also check that you have the latest version.

 

[simon12]

Must be faulty sensors

 

[simon12]

Just use the socket temp this is a sensor on the motherboard while the core is from the processor

 

[enzo matrix]

There is nothing wrong with the sensors. All of these sensors are simply inaccurate at lower temperatures. My friend's Phenom IIx6 sensor says it's running 19*C in a 25*C room on idle. Same thing.

 

[anoa]

Image on the left is system at idle for probably 10 minutes. Right image is while running Prime95 for about 20 minutes. Room temp is about 20C. This is 1.17.0 version of HWMonitor

I don't know if it is faulty sensors or just inacurate at low temps, but I'd just like to know if the temps are to be trusted while stressing the system. Are the cores actually only at 40C while running Prime95? Heck even if they are 43 or 51 (not sure which is the MB temp and the Socket temp) that still seems a little low.

 

[enzo matrix]

I don't know if it is faulty sensors or just inacurate at low temps, but I'd just like to know if the temps are to be trusted while stressing the system. Are the cores actually only at 40C while running Prime95? Heck even if they are 43 or 51 (not sure which is the MB temp and the Socket temp) that still seems a little low.

I would never let my temperatures on a K10 or K8 processor exceed 55*C.

if you want, some of us can use our experience with temperatures and compare ours to yours, in which case we need to know your exact cooling and case setup.

As a per example, I had an overclocked Athlon IIx4 620 at 3.2GHz without a voltage increase. load hit something like 50*C at 20*C ambient. I replaced the stock cooler with a sythe Katana III and now load hits about 42*C or something on extreme stress. I used MX-2 thermal paste for both and a dragon slayer case with stock fans raised on a desk.

 

[MU_Engineer]

Just put together a new system that included an Athlon II X4 640 and a Asus M4A785TD-M EVO. I am noticing very low idle temps. Using CPUID Hardware Monitor I am getting core temps around 12C with motherboard temp of 34 and what I believe they call the socket temp of 28. The ambient temp in the room is around 21C. The system is running the stock cooler as well.

I have been running Prime95 for about fifteen minutes now and the temps are up to 38 at the cores, 40 motherboard, 48 socket. The cpu fan has gone from 2100 to 3170 and the case fan as gone from 630 to 1130.

Do these temps sound right? The idle temp at the cores sound very low, since they are below ambient. Then they also seem low while running Prime95. The other two temps seem about right. Is there a known issue with this CPU that might report low temps?

I have also used Speedfan and CoreTemp and they are showing the same temps.

thanks

Errata #319 in the Revision Guide for AMD Family 10h Processors, pub # 41322 says that the thermal sensors in quite a few of the Family 10h (aka "Stars" or K10)-based CPUs may be inaccurate. The particular CPUs affected are all of the 65 nm original Phenom derivatives as well as the Barcelona and Budapest Opterons (steppings BA, B2, and B3), the quad-core Socket F "Shanghai" Opterons (stepping C2 only), earlier Phenom II X2/X3/X4 CPUs (stepping C2 only), all six-core Socket F "Istanbul" Opterons (stepping D0.) Note that the Athlon IIs are not affected by this bug. My guess is that your motherboard just miscalibrates your sensor, since it seems to be just reading uniformly low rather than reading erratically.