I would recommend at least 850 Gold or 1KW if you want to OC.
She use 25-50W more than normal GTX780Ti because OC and if you want to OC more with Voltage Tool can use even 150W more than normal GTX780Ti on air or water-cooling. On LN2 who knows how many power need.
GTX780Ti Classified 8+8 pin
GTX780Ti K|NGP|N Edition Classified 8+8+6 pin
I don't say 850-1000W only because graphic card, some space should be at least 100W and space for another hardware.
Imagine if you change for 2-3 years CPU and next need 200W, 3-4-5 HDDs collect during years and that's it...
Example if we talk about excellent 750W Gold PSU on 700-750W 12V rail will not be any more as on 500-600W.
If we talk about some II or III class PSU that will happen on 600-650W and could cause instability.
post edited by Vlada011 - 2014/11/23 11:28:37