I'm thinking about getting another gtx 680 for sli, my power supply is 700 watts. Is that enough power or do I need to upgrade my PSU? I am also willing to get a 780 as a replacement also, but getting another 680 would be cheaper.
Is it a good quality power supply? If yes, you should be fine, it looks like others are using 750 watt PSUs. If it's a no name or crappy brand then I would not recommend it.