Normal Temperatures on E8400 with Freezer 7 Pro


Dec 4, 2005
Hi i want to ask, if its normal to have on C2D E8400 with AC Freezer 7 Pro temperatures in load - Core: 59 C and in idle - Core: 48 C (measured with Everest Ultimate, CoreTemp shows about 4 C lower, why?) and Freezer RPMs are in idle 1300 and in load 1900. Is it OK? When I had Intel BOX stock cooler core temps went to 70 C in load. Ambient temperature is around 25 C. Thanks for answer.


Apr 18, 2008

The AC7 temp sounds about right. I'm using a Cooler Master Hyper TX2, which is about the same in size/perfromance from what I've heard. My E8400 runs at about 60C load, idles at 45C, with ~25C ambient. So that seems to be decent performance. I think your taking a hit from summer like I am. I used to idle at 35C in the winter, even with the core at at 3Ghz it idles at ~45 because of the increase in ambient.

Try RealTemp, this is the best one for 45nm cpu's and the difference in programs is from calibrations due to different developers calculating for 45nm differently.


Dec 4, 2005

Thanks for answer!
With Real Temp Core Temps are about 45 C idle (Everest shows 50).


Intel Master

There are several variables involved, so allow me to put the big picture into perspective for you.

Core 2 Duo's have a single CPU temperature sensor (Tcase), and two Core temperature sensors (Tjunction). For the E8400 C0, Intel's Thermal Specification is 72c, which is shown in their Processor Spec Finder -

72c is maximum CPU temperature (Tcase Max), NOT Core temperature, which is a common misconception among many users. Also, there's a 5c Gradient between CPU temperature (lower) and Core temperature (higher), which is shown in the following Intel document -

Although maximum Core temperature (Tjunction Max) is 100c, which is for Throttle and Shutdown protection, the corresponding CPU temperature would be 95c; far too hot for sane operation. As such, CPU temperatures above 72c and Core temperatures above 77c should be considered as an "overtemp" condition.

SpeedFan shows CPU temperature AND Core temperature, while Real Temp shows Core temperatures ONLY. Both programs allow calibrations. Intel has stated that the Digital Thermal Sensors (DTS) used for monitoring Core temperatures are accurate at very high temperatures, become less accurate as temperatures decrease, may "stick" below 50c on 45 nanometer Core 2 processors, and may be unreliable at idle temperatures.

On the other hand, the Analog Thermal Diode used for monitoring CPU temperature is linear from idle thru high temperatures, which is why, as per agreement with Intel, motherboard manufacturers do not include Core temperature in their monitoring utilities found on the installation disk, such as Asus Probe.

Never assume that default temperatures are accurate. The accuracy of CPU temperature is determined by BIOS calibrations, but can be closely calibrated in SpeedFan. The accuracy of Core temperatures are determined by Intel factory calibrations, but can be closely calibrated in SpeedFan and Real Temp.

Prime95 Blend, or OCCT (Linpack), or CPU Burn Test (LinX) are cyclic workloads, which produce fluctuating temperatures. While these are useful for stability testing, they're inappropriate for thermal testing. Prime95 Small FFT's is the standard for thermal testing, because it's a steady-state 100% workload. Since thermal saturation is reached within 7 to 8 minutes, a 10 minute test is adequate. Keep in mind that even the most processor intensive games or applications will rarely exceed 70% to 85% sustained workload.

From the Core i7 and Core 2 Temperature Guide:

Scale 2: Duo
E8x00: Tcase Max 74c, Stepping E0, TDP 65W, Idle 8W
E7x00: Tcase Max 74c, Stepping R0, TDP 65W, Idle 8W
E7x00: Tcase Max 74c, Stepping M0, TDP 65W, Idle 8W
E5x00: Tcase Max 74c, Stepping R0, TDP 65W, Idle 8W
E5200: Tcase Max 74c, Stepping M0, TDP 65W, Idle 8W
E4700: Tcase Max 73c, Stepping G0, TDP 65W, Idle 8W
E4x00: Tcase Max 73c, Stepping M0, TDP 65W, Idle 8W
E2xx0: Tcase Max 73c, Stepping M0, TDP 65W, Idle 8W
E8600: Tcase Max 72c, Stepping E0, TDP 65W, Idle 8W
E8xx0: Tcase Max 72c, Stepping C0, TDP 65W, Idle 8W<--E8400 C0
E6x50: Tcase Max 72c, Stepping G0, TDP 65W, Idle 8W
E6540: Tcase Max 72c, Stepping G0, TDP 65W, Idle 8W

--70--/--75--75-- Hot
--65--/--70--70-- Warm
--60--/--65--65--Safe <--
--25--/--30--30-- Cool

CPU temperature = Tcase
Core temperature = Tjunction

Also, Vcore Max for your E8400 C0 is 1.3625

Hope this helps,

Comp :sol:


Nov 20, 2007

Quote removed for post size isues.

Amazing! Thanks, what a refreshing expert input on Toms Forums.

You post at Xtreme Systems too?


I have a system running with an e8400 and Artic Cooling Freezer Pro 7. The e8400 is OC'd 24/7 to run at 3.2 GHz (8 multi X 400 bus spped) and my idle temps as measured by RealTemp are 37 and 44. Load Temps after 30 mins of Prime 95 are about 55 C for both cores and the AC Pro 7 fan ramps up to 2100 RPMs from idle 1300 RPMs.