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How to properly use Core Temp on AMD CPU

Posted: Fri Jul 19, 2013 11:16 am
by agaeon
After going through this thread it made me wonder what temperature Core Temp is actually reading. I'm using an AMD phenom II x4 955 black edition and this is what it displays at idle and at Prime95 load.

If I'm understanding that thread correctly, TCase is the value I should care about, and TCase should not exceed 62C on this CPU. However I don't know which, if any, of these programs display TCase . I believe the creator of Core Temp suggested to add about 15C to make it's default display value match the TCase value. However If I adjust the value to that level that would mean my TCase is 70C at load, which is 8 degrees above safe levels. I don't know how that could be because I've ran Prime95 for 24 hours straight at one point, and I'm using a Cooler Master Hyper 212+ on stock frequencies. I've had this setup for over a year now and I've played numerous CPU demanding games like Battlefield 3 and Metro 2033 for hours on end with zero ctds or blue screens. So either my TCase is infact not approaching those levels, none of these programs are displaying the TCase value correctly, or my CPU can take the heat.

Re: How to properly use Core Temp on AMD CPU

Posted: Fri Jul 19, 2013 1:59 pm
by Jorge
Tcase is what Core Temp and some other CPU temp monitoring programs report. AMD engineering advises that NONE of the current software properly measures AMD Tcase including AMD Overdrive - which they say will be fixed in the next iteration.

Do not be confused by temp software that displays "CPU" or similar temps. These are the mobo thermister located below the CPU socket. Under load this temp will read 15-25C higher than the Tcase, i.e. "core temps" because the socket temp thermister has no cooling.

While Core Temp is not exactly correct over the entire range for AMD CPU Phenom and newer CPUs, it is pretty close at temps above 40C and almost exactly correct in the 60C-70C range based on my extensive testing with Phenom II and FX processors. If AMD lists 62C as the max temp for your CPU, (it can vary by CPU model), then 62C is the max temp reading in Core Temp that you'd want to run your Phenom II CPU 24/7 under full load such as P95. Most CPUs never see their max temp unless you are running extensive video software or similar that can use all cores @ 100% concurrenlty or in stress testing like P95, OCCT, Linpack, etc.

Re: How to properly use Core Temp on AMD CPU

Posted: Sat Jul 20, 2013 5:16 am
by agaeon
Hmm, that's very interesting. Can you give a source on the AMD overdrive false temperature reporting? I can't seem to find anything relevant on google.

Re: How to properly use Core Temp on AMD CPU

Posted: Sun Jul 21, 2013 9:52 pm
by Jorge
AMD engineering reviewed the subject in detail at my request and confirmed the values shown were incorrect and they advised that the next iteration of AMD Overdrive would have this issue corrected. They could not advise when the next iteration would be released however.