Thxs to this thread and alittle help on IRC...I turned up my jup. to around 630-650gh/s on poolside 
thxs tolip great job and my HW errors down to .5%
Not enough information..That doesn't help anyone. What do your config look like? 4/8VRM? Etc. thxs tolip great job and my HW errors down to .5%Why not share information?
Changed the clock to 231 (plenty of how-to above).
Performance is steady 650-670 on pool, have 3 x8-vrm boards and 1x 4-vrm (RMA-d). Temps 43 (intake side boards) to 55 degrees, I lowered the fans for more flow over the boards.
Power usage (bertmod) from 451 W to 644 W (speed from 562 to 678 In cgminer), hw 3.5% (tightened the voltages a bit which increased hw-errot but reduced power/avoid it gets to hot.
Asic chips can handle more if I base it on the heat coming of them but don't know any higher clock frequencies as 231 ( besides that the vrm's are around their 40W limit already). Guess more juice can be pumped out if 8 vrms can be activated again!
I wish there was a firmware with that to the nov as well.
So, has anyone tried this on nov. unit except from me? Those negative results (340+ -> 333Gh/s at best) is making me sad