For those suggesting the 9590, its the same CPU just its default clock speed is higher and it consumes a huge amount more power and runs extremely hot. In truth the 9590 is the fastest, but since it costs quite a bit more and an 8350 can be overclocked to the same speed they really aren't worth considering.
As for performance:
https://www.youtube.com/watch?v=4et7kDGSRfc
See that video review, particularly the last half. Its looking at it overclocked but the FX 8350 wins by a larger portion when both of them are at their stock speed because the i5-3570k overclocked a lot further.
The FX 8350 won in:
Crysis Warhead 1440p, 1080p were close
ARMA 2: 1080p and 1440p FX 8350 beats it by a huge amount
Farcry 3: 1080p and 1440p FX 8350 still way higher.
Metro 2033: i5-3570k wins in all scenarios
Natural Selection 2: FX 8350 wins all scenarios
Skyrim: Mixed results
Trine 2: Mixed results
A lot of other games show this. The FX 8350 is much much faster than the 4350 in pretty much everything, always. It also often manages to top the i5 for gaming.