i7 cpus are a waste for gaming or so i read, a latest i5 chip would be a better choice, mine is a i5 4570 (haswell) with a gtx 670 gfx card and 8 gb ram, plays bf3 easily on ultra at 60fps+ @1920x1080
bf4, being the newer game, might run at slightly lower fps but u can always drop a few settings down to high
i'd also go for a higher rated PSU, look for a 750watt branded such as corsair, spend around £60+ and not £20 on a ebay one
http://www.anandtech...bench/GPU12/372 - gives u some idea of performance, although some of the newer components aren't listed like the "new" R range from AMD (mostly rebadged older cards) best to do a google search so u don't get ripped off.
a quick google search - http://www.bit-tech....-260x-reviews/1
Let us know your budget and we can try and help you