|You should list all your system specs. There's no point getting a high end video card if you have a weak CPU, it will only be bottlenecked. And you definitely will need a decent power supply, especially if you're planning to run two cards in SLi. You don't necessarily need a high wattage PSU (1000W for example), but you do need one with high amperage. And units with a single high amperage +12v rail are generally better than units with multiple +12v rails. The following article will help explain:|
Power Supply Myths Exposed!