I have it set to 1.4-1.55v depending on...my mood, really
I have never had issues with the vNB with 2 or 4 sticks.

I also went a step further and removed the Chipset Heatsinks, cleaned the factory crappy putty off, and put Arctic Silver Ceramique on the NB, SB and Mosfets that are covered. I also did the same thing to the Heatsink that is above he CPU at the top of the motherboard, plus I have a 120mm fan blowing down on the RAM and NB. The NB is not even warm to the touch.

That might explain why I have virtually no NB issues with heat.

*my q6600 is lapped as well, along with my "Leaning Tower of Pisa" Thermalright Ultra 120 Extreme