The FX is stronger in multitasking and applications that require several cores, single core apps is weaker. The i5 has stronger cores so handles single core (or few cores) apps better, it can be overclocked but it still remains as a Quad-core CPU. Tech-wise the FX is older and supports less processing instructions, also the AM3+ socket is a dead end with no future upgrades, still a decent CPU for gaming and rendering but limited in possibilities.