Well, I think I managed to get the system stable at 4.0 GHz after OC'ing for nearly 5 hours. Here it is:

Frequency.............................4.0 GHz
Clock Ratio............................20x
Bus Speed.............................200 MHz
vCore...................................1.344v idle | 1.328 v load --- 1.38125 in BIOS
QPI/VTT voltage.....................1.32v
DRAM...................................1.58
Uncore Frequency...................3200 MHz
QPI Link................................x36 (7.4 GHz)
Performance Enhancement.......Standard
Memory Multiplier...................8x
Memory Speed.......................1600 MHz

I realized that the vcore voltage was the biggest limited factor. Haven't tried to lower the DRAM/QPI voltages yet.

Questions: Do you guys think that my vCore voltages (1.344 idle/1.328 load) are safe to be running at 24/7? On 100% load, the temps hit 80*C and they are 44-46*C at idle.

Should I drop it down to 3.8 GHz where I had vCore at 1.216v idle / 1.20 load? Temps were about 5*C cooler...

Thanks for the input / suggestions.