Z640 is NOT really running hot

[wavetrain]

Response to my previous thread No fan control on Z640 with Windows 10 (now locked)

If you look up the Intel product specifications for the E5-2667 V4, you’ll see the following…

TCASE Case Temperature is the maximum temperature allowed at the processor Integrated Heat Spreader (IHS). It’s listed as 78C.

So my CPU temperature should be 78C. That was easy. And now I use a utility to measure it and I’m seeing temps in the 80’s. Something is very wrong here. So I try to figure out why my processors are running so hot. But the answer turns out to be very simple.

There is no way to measure TCASE with onboard sensors. It’s a number provided for manufacturers using specially instrumented CPUs. What you’re really seeing with HP Performance Advisor is Tjmax or Tjunction max. Average, highest? Who knows. These are the core temperatures that the system uses, and are responsible for things like thermal throttling. This temperature runs significantly higher than TCASE.

I found a nice little utility called HWINFO64. It will record system info to a file. Then open it with Excel to review everything going on with your processors. Among the fields reported are individual core Distance to TjMAX values. So even under 100% CPU utilization with Tjmax scores in the mid 80’s, you still have a good safety margin. It will also tell you if there is any throttling. I ran a 100% load overnight, and my Z640 held together just fine.

So it’s not so hot after all.