I just checked out Tom's Hardware's Gaming CPU Hierarchy Chart for March 7, 2012. http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html
The FX 4170 is ranked as the fastest of the AMD processors... in the same tier as the 1st gen i7s... faster than the FX 8150 and the fastest Phenom II X4s.... Is this accurate??
Yes. I have been following the FX 4000 benchmarks for a while. The 4170 is the best gaming part, at stock speeds at least.
I think its due to the fact the most games don't use the extra cores and that there is twice as much cache per core on the 2 module parts. All the FX parts, regardless of core count, perform within 5% of each other in games at the same clock speed. And the 4170 is, by far, the fastest clocked FX part.