Hello,i have a big problem, and i hope that somebody can help me to resolve it. I have Gigabyte motherboard ma770-us3 rev. 2.0 and i unlocked the 4th core on my athlon II x3. The 4th core works great, i have a 6mb L3 memory, but my display drivers stop working after unlocking the 4th core and there's nothing i can do. It simple won't working and the screen on monitor became unstable. I have Sapphire ATI HD5670. I've tried updating bios and reinstaling display drivers but still the same. The computer send me report something about " no digital signature" after stopping drivers. Please help!!!