I tested and sold a rig exactly like this, except it was FX 6300 + R7 260x. The GPU and CPU needed to be OC'd or I had severe dips (GPU extra 100Mhz and CPU at least at 4.1 Ghz with no clock dropping). Once I OC'd I got smooth gameplay on high in bioshock and tomb raider (dips into 50's, up to 70/80/90's fps at certain points in benchmarks). I used the build in bioshock benchmarking utility, likewise with tombraider