MEC-777 :
About 4 vs 8 cores... Since Intel per-core performance is significantly higher than the AMD FX, when you run a program that is able to make use of 6-7 cores, the Intel CPU is able to do the same work in the same amount of time because the Intel's are doing more work per-core.
Let me step in here, as this isn't accurate. In programs that run 6-8 heavy threads, the AMD does win. It's documented many times, many places. There are not a great deal of situations where the program actually runs that many heavy threads, but it does happen occasionally.
If you look at rendering, that is the only situation where the program will fully load all the cores of whatever you throw at it with several different programs operating this way. This is why the 8350 destroys any i5 at rendering, and i7's keep up.
This shows you what you're looking at:
http://hwbot.org/compare/processors#2741,2493,2743,2495,2689-57,94
In Cinebench R15, the 8350 is way ahead of the i5's and in HWBOT Prime (their own benchmark) the 8350 is ahead of even the i7's on the list there.
So, Intel is not always equal or better...it depends on what you're doing. However, for gaming, the performance will be close enough that you should build the best system you can, if that means saving $50-100 buys a better GPU or SSD, then do that...don't get caught up in the processor wars...it isn't worth fretting over.