He pointed me to the right documentation, but I looked it up myself. As such, I'll see what I can find since I know where to look now.

It appears as if the NB is subject to the same MaxVID and MinVID as the processor itself. At least this means I should be able to jack the NB to 1.225V if nothing else. It defaults to 1.1x. Who knows if that's what was actually becoming unstable instead of my cores. They clock synchronously on my system. CPU Clock = NB Clock