Guys, please make this clear - have you achieved more hashing power (stable long-term h.p. both at miner's and pool's side with normal reject/discarded/stale/HW rate) after S2 overclocking or not?..

Also - what firmware do you use, what clocks have you set?
I will today replace 2 big fans with Noctua NF-A14 PWM (to see whether it will work more quiet having the same temperature), replace PSU with Chieftec 1250 W and try to OC it.
