you guys could try building the spinlock kernel for sm_20 to check if you'll be getting your previous speeds back when running it on a Fermi device
Still crashed cicc when sm_20, went ok with sm_13. Testing against 2013-12-01, 2013-12-07 spinlock is about 5 - 6 khash/s faster.
With fermi kernel 2013-12-01 with the added offset is around 233, 2013-12-07 is about 228. I tested 2013-12-07 with both your precompiled exe and self built from source, results are identical.
Id like to see feedback from more fermi owners. In particular compute 2.0 fermis and even more particular 448 core gtx560ti.
Well i have a pallit one anyway. Cheapest i could find but that shouldn't cause my results to be totally different to yours. I don't think its a problem with os or drivers because i dual boot 32 bit debian and get the same results there.
Although i cant really see it, maybe my weird ddr3 + fsb + pcie 1.1 abomination is causing it.