AMD X3 720 Unlock Fourth Core
Socket AM3 X3 720 + Gigabyte MA790FXT-UD5P.
Used @Bios to update originally shipped bios (which was flaky as I bought this board when AM3 FIRST came out) and it didn't have the ACC option.
I have NOT been able to replicate the same results with an X2 240 with a Gigabyte MA785GMT-UD2H motherboard even with ACC options available though that system is for a family member who simply surfs the web.