"EAT AT JOE'S"
According to Bottleneck calculator, the 580 is too slow for this CPU already. Wouldn't buying a cheaper GPU make that issue worse?
I've been toying around with PC builds here and using RAM UserBenchmarks and Bottleneck calculator. According to the latter site, this CPU/GPU combo would produce an average bottleneck percentage of 31.48%. Isn't that pretty high? Using a better GPU (GeForce GTX 1070) would work, but it adds $135.00 to your build. Lowering your CPU down to an AMD Ryzen 5 2400G effectively eliminates your average bottleneck percentage (.001), but you lose two cores. I don't overclock, but would love to wrap my brain around the idea. Could you overclock your GPU in your build to compensate?
GPU is too slow for your CPU. Probably bottlenecking 40% of the time