I was wondering if I bought a Corsair HX650w if it would be enough to power a Intel 2500k, 8 gigs of g-skill 1600, asrock extreme 3 z68 mb, gforce gtx 560Ti 448 core GPU. Or would I have to up the PSU to maybe the 750w.
For a system using a single GeForce GTX 560 Ti 448 Cores Limited Edition graphics card NVIDIA specifies a minimum of a 550 Watt or greater power supply that has a combined +12 Volt continuous current rating of 38 Amps or greater and that has at least two 6-pin PCI Express supplementary power connectors.
For a system using two GeForce GTX 560 Ti 448 Cores Limited Edition graphics cards in 2-way SLI mode NVIDIA specifies a minimum of a 750 Watt or greater power supply that has a combined +12 Volt continuous current rating of 60 Amps or greater and that has at least four 6-pin PCI Express supplementary power connectors.
Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Continuous Amperage Available on the +12V Rail(s) is the most important factor.
The Corsair Professional Series HX650W (CMPSU-650HX), with its combined +12 Volt continuous current rating of 52 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with a single GeForce GTX 560 Ti 448 Cores Limited Edition. It is insufficient to power your system configuration with two GeForce GTX 560 Ti 448 Cores Limited Edition in 2-way SLI mode.