I want to know if I were to use a GTX 980 with a wimpy FX-4350 what the expected FPS would be. Please give a serious answer, don't say: "you need to upgrade or you will get bottlenecked", because I know.
You'll get playable FPS (with a share of stuttering), but if you have a 120/144Hz monitor the FX 4350 won't be able to maintain that no matter how good the GPU is.
But who the F combines a FX 4350 with a GTX980, if you had the money for the GTX980 then you'd have the money for an FX 8350 or an Intel or something. Or could've gone with a GTX770/960 or R9 280/285/380.
Just don't expect 60fps ultra on everything - 45-50fps on high is a more likely scenario.
If you don't already have the CPU , you would be better off with a pentium g4560 , a b250 board & ddr4 ram - would work out about the same price buying new.