I recommend the SLI approved PSUs, as those are supposed to avoid any power bottlenecks due to the videocard. The problem is some PSU's are rated at different temps. As a general rule of thumb, the higher the temperature, the lower the wattage output. 50 degrees is typical of server level PSUs, which are designed for high temperatures. The Seasonic 600 Watt PSU received high praise from THG. Perhaps said PSU might be right for you.