FX-4170s (or any Bulldozer) have more L3 cache than they need, at least as I recall reading a big long article about the Bulldozer architecture, that one of it's flaws, not strengths. I wouldn't focus on that too much as a selling point. The PileDriver 4300 is a step up, and thats the direction I'd probably go.
Which would you choose? the FX-4170 has a higher stock clock and more L3 cache (8 MB vs 4 MB), but also a higher TDP. Why do you suppose Piledriver reduced the amount of L3 cache? Thanks!
both are about the same performance- but 4300 is better- + you can OC it to the same 4.2 Ghz as the 4170 and it will outperform the 4170
i would go for the fx 4300 becasue buldozer was crap and the fx 4170 was much of a upgrade form x4 955be