I'm having a problem with a Phenom 9650 and an ABIT AN-M2HD Mobo. (I upgraded from an Athlon 64 4800 X2) The CPU reports 60° at idle, with the clock freq @ 1/2 speed with cool & quiet enabled. This also matches the BIOS temp. When I monitor the core temps with Everest or Speedfan, the cores are around 38 - 40° at idle. I was using the stock heat sink with Arctic Slver 5. I unseated it, cleaned and added new paste but got the same result. I upgraded the heat sink to just a slightly better copper model but this only gave me a 2 - 3° difference in all temps. When I run the CPU at 100% (Video processing) The reported CPU temp gets to 88°, (The mobo shuts down at 90°) and the Everest core temps report 59°. I do not see any performance issues. I have the mobo bios to the latest at Ver 20. I can revert back to 19 which is the earliest that supported the AM2+ CPU's. I havent tried that yet.
I sent an email with all of my test results to ABIT but got no response. I also spoke with AMD. The advice there was to esure that the heat sink has good paste and is seated correctly. Feel the bottom of the heat sink at idle. If it is hot to the touch then the reported temps may be real. Mine is not at idle. It is luke-warm. He then said to run the cpu at 100% for 10 minutes and feel it again. If the CPU is truly at 80°, it will be very hot to burning to the touch which makes sense i suppose :-)
Other notes - The mobo also reports case temp and PWM temp which are 32° and 42° respectively, at idle. I've also seen similar issues with other ABIT boards and phenoms.
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The Phenom CPUs don't have individual core temp sensors, only an overall chip sensor, so ignore the core temps. Since your MB doesn't officially support the x4 9650 (it only supports the 9600 and 9500), who knows if the BIOS temp readings are correct. I wouldn't worry about it.
PS - Abit is out of the MB business and doesn't have any more tech support, which is why you didn't get a reply from them.
As far as the individual core temps... They do seem to read the same value... I have to wonder what they are actually reading. Perhaps it's the actual CPU temp. It would be about right for normal operation...
Anyway... all I can do is ignore it I guess unless someone hacks the bios.