I have a AMD phenom II 945 quad core processor. For the past year or so, when i boot up i see the display that says 4 cores are active...now for some reason i see 3 cores are active...What happened? can it be put back? any programs that anyone knows of?
Sounds like ACC maybe enabled for some reason. Pretty sure the splash screen should read something like "press 4 to activate all cores" if ACC is disabled, and when enabled it tells you how many cores are active 4,3,2.., even on a native x4.
Make sure Advanced Clock Calibration is disabled in your bios. page 3-18 in your manual
Go to Advanced/CPU Configuration/ and make sure "Advanced Clock Calibration" is "disabled".
If that doesn't help try clearing the cmos,page 2-20 of your manual.