As I imagine you know it doesn't really work in absolutes. Iirc the community advice for a P45 system was to keep fsb term and nb voltage at or below 1.4V for continuous operation on generic air cooling.
If it's a trial to see if too little nb voltage is the problem, then go for it. If it's a long term solution then I'd be more cautious. Naturally the cooler the northbridge, the higher the voltage you can push through it. If you've not yet taken the stock cooler off, scraped off the oem paste and replaced it with mx2 or arctic ceramique this is well worth considering. Gigabyte and Asus honour warranties after this has occurred.
Changing northbridge strap may be a better route to try, if the internal timings are looser it should operate with a lower voltage.