i think he used the cpu voltage to offset the cpu vdd and control the amount of vdroop when on load, not sure though but that is how i configured mine, cpu vdd = cpu v +0.025.

with regards to nb, i think there's a problem with the newer bios clocking them higher with the 720BE because i am also experiencing the same problem. i can't clock the nb higher than 2600mhz from 1.5b7 but with 1.5b1 i can clock it up to 3000mhz