1. I am also using K10stat, and the methods you use are fine, I used a very similar approach. 2. Same as for P0 and P3. 3. You cannot permanently set it, every time you restart, these settings are lost. But you can save a "profile" in K10stat and then create a shortcut in Windows Startup folder, lik...

I had a similar issue with my old Athlon 64 X2. Prime tests were 100% stable, yet it would crash the machine in normal everyday usage. Turns out it was switching between states that caused the crashes, like Klusu said. I solved it by manually setting the lowest possible voltage and fixed 10x multipl...

I got my 620 down to 1.125V full load and 0.925V idle, on Asrock ALiveNF7G-HDready. Maybe could have gone lower in idle, but this board doesn't have split voltage for CPU and NB and 0.925V is probably the low limit for the NB. Of course, C'n'Q enabled in the BIOS, and P-states' voltages modified usi...

I see your X4 630 has AACYC markings, which indicates that it is possibly based on a Deneb core with L3 cache disabled. Have you had any success "unlocking" it using ACC option in BIOS?

I have an Athlon II X4 620:

Stock: 2.6 GHz @ 1.4V
Undervolted: 2.6 GHz @ 1.125V

Lowest P-state (stock): 800 MHz @ 1.15V
Undervolted: 800 MHz @ 0.925V

This is on AM2 board, though (NB runs on same power plane as the CPU). Maybe with an AM3 board one could lower the voltages by 0.025V more.