The i7 is four physical cores with hyperthreading, which equals eight core processing. AND, single core performance on Intel processors is MUCH, MUCH faster than single core processing on AMD processors. So pretty much any comparison with a similar number of cores is going to go to Intel in every case. Even the four core i5, with lower clock speeds, beats the FX chips in the majority of tasks, especially gaming, but also threaded processing of applications as well. There are situations where the FX chips beat the i5, but I haven't seen any, or at least very few, instances where they beat the i7.
It's all about core performance and number of clocks per cycle, which AMD is way behind on.