To determine what processor your motherboard can handle we need to know what motherboard you have. We need to know how many watts your motherboard can support and what power phase your board has. If you only have 4+1 power phase your best bet would be the FX 8320E or at best the FX 8370E. If your board can support 125W and has 8+2 power phase or better the best upgrade possible is the FX 8370.
I would stick with the FX 8370, 8370E or 8320E as they are all part of the FX refresh, have the latest tweaks from AMD and have the best binned silicon. All these things will help the overall performance and power usage of the processor. The FX 8370 is AMD's best overclocking processor as it has performance tweaks over the FX 8350 and has...