Sep 14, 2009
Trying to unlock 4 cores on this cpu, but when ever i enable ACC and save and exit bios it wont reboot and post... dont know what to try really tryed incresing cpu voltage and core voltage no luck...

to be honest im not used to using amd processor and amd mobo's....

used to intel... so ht link, cpu-nb etc mean nothing to me....

also just overclocking with just 2 cores enabled im struggling with the best overclock ive managed is 3.8ghz... which im sure i can push higher...
system specs are

550 be
spphire pure crossfire 790gc mobo
8gb xsm2 1066 mhz ram
corsair hydro h50 cpu cooler
corsair vx550 psu
sapphire 4870 2gb vabor gpu
antec 900 case

any help appreciated....


Dec 22, 2007
Clear your CMOS and set your ACC to Per Core -2% (not Auto or All Cores). You should see four lots of -2% in a column against Core 0, 1, 2 and 3. F10 (save) and see what happens.

If the other two cores are non-functional, nothing will help. I don't mean locked so they don't function, I mean non-functional = D-E-A-D.

If they are faulty, it might boot, crash, BSOD, again, nothing will help. You can pour the volts into faulty cores and it will not get better.

If they are functional, but locked, then unlocking will work just fine.


Aug 19, 2009
I have a Gigabyte 785 board and the 550 BE, set ACC to Hybrid and Auto and came up fine. As said, maybe yours just won't work - have been reading and that's true for many. But also, some of the newest BIOS revisions are designed to turn off this feature, so you may be in that situation. Might check to see if there are earlier revisions. (I'm no expert on this tho!)

One thing I'd try is to reset your BIOS to defaut or optimal conditions. What if the quad core won't run at 3.8? Don't know about this, but I'd try it. Shouldn't need extra Volts on CPU or core.