So i have about a £650 budget to upgrade my current 6970. After looking around it seems like my best bet is either two 680's or two 7970's. So im asking which would be the better choice, in benchmarks they seem to be pretty even in performance and price. the cards im looking at is are the MSI gtx 680 power edition or the MSI HD 7970 lighting boosted edition (MSI fanboy alert). Im not bothered by amd's never settle deal since me and my friends already own the games we want that they have on offer. Also buying something like a 780 or a 290x then buying a second card in a year or two isnt an option for me since im starting university next year and im not going to be able to spend any money on upgrading my pc for a couple of year after this.
Any suggestions are welcome