No fx 8320 is a beast , It won't be a bottleneck for any GPU, my piece of advice for you is to buy fx 8320, since you can overclock it to 4.0 ghz and change it fx 8350 and also with a decent cooler it can be easily overclocked to 4.5ghz, also you might want to look at these benchs of fx-8350 to see how powerful this beast is
http://www.techspot.com/review/591-medal-of-honor-warfighter-benchmarks/page6.html (MOH warfighter fx 8350 performs as well as i7-3960x)
http://www.techspot.com/review/601-black-ops-2-performance/page5.html (call of duty black ops 2 fx 8350 performs as well as i7-3960x)
http://www.pcgameshardware.de/Crysis-3-PC-235317/Tests/Crysis-3-Test-CPU-Benchmark-1056578/ (crysis 3- fx 8350 better than i7 3770k and just below i7-3950x)
http://www.hardwareheaven.com/reviews/1598/pg6/amd-fx-8350-processor-review-battlefield-3.html (BF3 )
www.hardwarepal.com/call-duty-ghosts-benchmark-cpu-gpu-performance/5/ (COD ghost Identical performance)
www.hardwarepal.com/battlefield-4-benchmark-mp-cpu-gpu-w7-vs-w8-1/4/ ( battlefield 4 ultra HD FX 8350 equal to i7-4770k)
www.hardwarepal.com/battlefield-4-benchmark-mp-cpu-gpu-w7-vs-w8-1/8/ ( battlefield4 full HD the same scenario)
www.hardwarepal.com/batman-arkham-origins-benchmark/8/(batman Arkham Origins fx 8350= i7 4770k after AMD's catalyst release)
so no you can't go wrong with fx 8320, overclock it to 4 ghz and it is fx 8350,
Don't forget to close the thread if you feel you don't have any other questions