Re: How Many Amps on the 12v rail for GTX 280 SLI
Q6600 @ 3.0GHz, 8 GB of DDR2, eVGA 780i motherboard, 2 10k 80 GB Raptors, 320 GB 7200 + 750 GB 7200 SATA drives, 2 optical drives, and 2xGTX280's @ 681MHz Core/1253MHz Memory/1466MHz Shader.
All on a Coolermaster Real Power Pro 750W with no problems. (It has 76 Amps across 4 12V lines)
So you should be fine!