I have recently decided to buy a new GFX as the one I have currently is getting outdated rather quickly with new games and software. I stumbled across the GTX 770 and feel that it won't cope with my PSU. At the moment I don't know my specs on my PSU but I knows its a Enermax either a 480W or 500W. I am hopefully getting a new one around the new year when I get some more money as Christmas is over. Can provide a dxdiag if needed.
As long as the PSU has a maximum combined +12 Volt continuous current rating of 37 Amps or greater and has at least one 6-pin and one 8-pin PCI Express supplementary power connectors it should be sufficient.