After looking at my board, I am 99% sure your mountng will fit fine on the EVGA 750i. There is a keep-out area around the socket to make sure there is some kind of standard. I didnt see any parts violating the defined rules. The mosfet heatsink is far away, so I am very positive, there won't be anything in the way for the mounting.

I am running 9800 GTX SLI right now and it works flawlessly. Will post some screenshots and results later. I switched to a 4 GB DDR2 kit aswell and I am running 400 MHz 4-3-3-4 right now. No problems at all.