I can't seem to stabilize it for anything over 4.4. What is the difference between "CPU NB voltage" and "NB voltage"?
Most of the overclocking guides for the phenom 2 are before the 990 chipset so I think things are different. I am putting 1.64 volts to the cpu right now and it still restarts in almost the exact same spot every time during benchmarks which makes me think I am missing something or the NB isn't what it should be. My temps never get above 54 C at full load. Board temps are always under 38 C too so no issue there.
Messing with the HT link speed and voltage seems to have no effect on stability. Right now I upped the "NB Voltage" rather than "CPU-NB voltage" and im going to try to run some benchmarks after class.
Also I disabled LLC as it was causing issues. I know for other cpus this is needed but seems for my setup it was causing problems.
Chances are that you wont get stable over 4.4, because like a mentioned a few posts up, these chips need cold temperatures to scale very much past that.
CPU-NB voltage is what you want to be raising for NB clocks. Try to aim for around 1.35v - 1.40v to get a NB of around 2.8ghz to 3ghz. Also try to keep the HT link close to 2000mhz, because its the most stable there and it doesn't really increase performance if you raise it.
Don't mess with the NB voltage. This voltage helps the FSB to clock high, but it's not needed unless you're shooting for 350+ fsb.
Also, these chips tend to get unstable when approaching 55 C, so try to keep it lower if you can. Below 50 C is a good temp to shoot for.