The voltage jumps hardly ever seem to be even, especially when you really start pushing. You may find .035 @ 4.2 works and then to get to 4.3 you may need .1, I'm just using it as an example. It's just the nature of the beast, there will become a point where the amount of Cpu V it takes to get to the next level just isn't worth it. That can only be determined by you though. Nice clocks BTW.