What about the rest of the components.? You need to provide info on the processor you are using and any overclock that you may have performed on it.. Do mention your budget also.. Meanwhile, a good 450W PSU (like the Corsair VX 450) is enough to power a single GTX 260.. Considering an overclocked processor and other standard components (hard drive(s), optical drive(s) etc.) a good 550W PSU should cut it..