Originally Posted by
davidw8818
Couple things:
1) ACC may not help much with locked CPUs, ACC will help to extend CPU core frequency clocking. If the limitation is something else (lets say Memory, HT ref. clock, Power) then the benefit of ACC is not optimal
2) typically you want to use AUTO setting if running with 9850/9950 and aircooling, more extreme conditions may like +4% or +6% - 9600BE usually prefers +4 or +6% at increased Voltage levels
3) negative values might be beneficial if trying to tune the CPU to run with low voltage settings (silent HTPC but still with max clocks) - low voltage meaning less than default Vcore
4) IGP in the Chipset doesnt have an impact on the Overclocking capabilities of the mobo (HT ref. clock etc)
5) CPU Voltage slider (CPU VID) range is defined by the CPU: unlocked Phenom CPU (Black Edition) will allow up to 1.55V, locked CPU (non-BE) has a limited VID range (e.g. up to 1.25V) - the motherboard may have VID override or OFFSET capability that allows running beyond max VID value. This may or may not be adjustable via AOD depending on the Motherboard and the implementation. Its a good idea to monitor the Voltage levels when adjusting Voltage / OFFSET value from SBIOS.
6) ACC being unavailable with SB750 could be SBIOS issue or SW bug in AOD. We have certain cases where AOD cant detect ACC capability properly (even if SBIOS is 100% fine). Some of these problems are now fixed with 2.1.3 release and the remaining ones (AHCI/RAID mode in particular) are taken care of with 2.1.4 that will be available soon. Just to make it clear: ACC will not be visible in AOD if you run in AHCI / RAID mode with version 2.1.2 or 2.1.3. 2.1.4 will fix this.
Please update to AOD 2.1.3 - LINK
This solves a couple of bugs that depend on OS environment (the crash bug for instance).
If ACC is not available thru AOD then you could use the SBIOS ACC control for time time being.
BY: macci
Heres ACC -2% at 3.7ghz it needs 1.456v which is +100 in bios to be able to prime 10hrs.
Heres are the results after changing ACC in bois to -4% which it brought down the vcore from +100 to +50.