That depends entirely on exactly what you want to do.
Some applications work best with the i7-4770 (moderately threaded with significant dependence on single-threaded performance), others are better suited for the i7-49xx (more significantly threaded with still significant single-threaded dependencies), others for the FX83xx (significantly threaded with moderate to low single-thread performance dependence) and then you have massively parallel x86 software which could scale to server CPUs like a multi-socket Xeon E7-8890v2 (15 cores / 30 threads per CPU, up to 8 CPUs per system - 120 cores / 240 threads per system) at $7000 per CPU for massively scalable code like software rendering, finite element analysis/simulation, signal processing, etc.