Anyone managed to push theirs past 225?
Every time I 250, it jumps up to 1275W in, but beeps constantly and eventually drops back down in 5-10 seconds.
Edit: At 225M I get 1153GH/s using 1148W using an EVGA 1300W G2 on 115V. It will probably be a little better on 240V, but I don't have per-outlet metering on my PDU and I wanted to get power measurements using my KillAWatt.
Every time I 250, it jumps up to 1275W in, but beeps constantly and eventually drops back down in 5-10 seconds.
Edit: At 225M I get 1153GH/s using 1148W using an EVGA 1300W G2 on 115V. It will probably be a little better on 240V, but I don't have per-outlet metering on my PDU and I wanted to get power measurements using my KillAWatt.
To get it running @ +225Mhz I would suggest to up the voltage to 0.85V... Get out your pencil!!
Where's the rocket scientist when u need one?
check the overclocking thread. There will be two resistors associated with the output voltage of the TPS53355 regulator. using a pencil mod on one will increase voltage and pencil modding the other will decrease it. Figure out which one ups the voltage and go to town - 0.9V will probably unlock ~1.25TH/1350W. 0.95V might be sufficient for up to ~1.35TH/1.6kW if you can cool it a lot better then stock
I have a S1 on 0.86V and max clock is 250M (128GH), with 164W at the wall. 275M gives 138GH but over 10% HW error and 180W consumption.
sounds about right then - the S2 is basically 10 S1 units running at clocks similar to your current ones (ps: why dont you run your S1 at stock clocks right now - You would be making a lot more profit then with your underclocked speeds)
A small pencil mod to increase to S2 voltage should make >1.25TH possible. The PCI slot seems to use mutliple pins on a common blade of the cards to provide voltage. It looks pretty good method, and it *might* work with a ribbon cable, but a fat pair of 12AWG wires to carry the voltage would be the best way
MrTeal - what sort of temperatures does it hit at 225MHz - did you modify cooling?
I have more than one S1. I ghettoed one just to check performance and durability of the pencil mod. It runs at 41-43 degrees C ( room temp. 20C ), 1320RPM fanspeed and 3 HW errors a day in average!
I appreciate seeing the voltage/speeds/wattage results posted for these sort of mods, so tip of the hat
For me at $0.15/kwh it makes more sense to run all my gear at full tilt (under 0.7% hw errors of course) for at least until the start of summertime 
