just get an 850w PSU and you will be fine. I have 860w corsair plat, 850 thermaltake gold and both have been running for many months without issue. Watts at the wall is around 810. Say 10% loss (conservative) it is only at 730watts.
PSU's are not rated for what they draw at the wall!!!!!!! They are rated for what they can deliver to the device.
would that work for 2 oc'd ants though?

I've read some guides here that say 850W would be just fine for running them @180g/h (stock)
are yours oc'd and both running on the 860w corsair?
thx so much for your fast replies guys