Asrock AOD790GX Cold Boot problem with Phenom II 720

[Summer Leigh Castle]

My system powers on from a cold boot with with no signal to the monitor or hard drive usage when I turn ACC on in the bios (to enable the 4x cores). Temporary solution to get system on with 4 cores is a simple restart after the cold boot. I've read a few forums and some people are getting similar problems yet no one has found a viable permanent solution. General consensus so far point to the motherboard with a possible future bios update from the manufacturer but I've yet to receive any support from Asrock (or rather, any body so far). Any ideas, solution or similar experience?

CPU: Phenom II 720x3. 0904EPMW. 4x cores stable @ 3.5ghz 1.45v with back to back 4HR total test using OCCT and Prime95.
MOBO: AOD790GX/128MB. Bios 1.4 (current).
VIDEO: Radeon 4850
MEMORY: G.Skill PC6400

And yes, everything runs fine with ACC off (with the exception of losing the 4th core). I could manage restarting the computer once after every cold boot but a part of me doesn't feel right.

Thanks all!

UPDATE: Board has been RMA'd. One thing going for Asrock is their super fast RMA process. Replacement board in hand after only a week. Very impressed.

 

[Guest]

I have the same issue with my Phenom II 720 x3 when I enable ACC in my BIOS of my GIGABYTE GA-MA790GP-UD4H motherboard.

I find that switching off my PSU, turning it back on, and then pressing the power button will allow me to start the computer and work properly. I haven't found any posts that know how to fix this problem save turning off ACC or flashing the BIOS (which i hear in gigabyte motherboards removes the ACC option). Both of which doesn't help me in keeping my 4th core AND resolving this cold boot issue!

Does anyone know how I can have my cake and eat it too?

 

[Summer Leigh Castle]

Same symptom as before but now system hangs at startup even after a reset with ACC off. Asrock tech support suggest to RMA as CPU worked fine when I switched it to another motherboard.