Re: Asus gtx 285 in SLI mode
You can calculate what your system will consume around with eXtreme Power Supply Calculator. you can download it from extreme.outervision.com. for your information Both cards will be at the same speed. You can have a non-top version in addition to, but the speed of the slowest card accepted by the top variant.
Re: Asus gtx 285 in SLI mode
Cooler Master Silent Pro 700W with a 12V rail of 50A provides 400 or 500W do not know exactly, especially so for SLI. see the specification of your power supply to the 12v line. Heavier power supplies designed to have SLI if it is a separate high-12V line amps and suitable for SLI.
Re: Asus gtx 285 in SLI mode
Dont give too much importance to the power supply wattage, see weather it can deliver the 12V lines, efficiency and construction quality. This 850W power supply you will however be sufficient. I have seen people running GTX295 at 1.25v running at 775MHz on a 800W power supply. 850W will be enough for So 2 standard GTX 285.