You really should learn the definition of bottleneck. His gpu can be replaced last, also I said 60 fps doesnt give you more benefits over 30-40 in THIS game. Also, 4590 vs 6300 can't even be compared. It's comparing a apple to a pear. The 4590 has 42% better single core, 52% faster quad core, 11% faster multicore, So where did you get your 3-5%? the i5 4690 is 15% faster than the i7 3770k. Him buying either the GTX970 or the R9 390 will bottle neck his PC. Even with a 960 or 380 there is a chance of bottleneck. His FPS will spike from high to low and in some cases it will give him a lower performance than he would've had with his gtx 660. This is the reason I've said he should focus on everything but the gpu.