I'm about to by a new CPU, motherboard and RAM. I'm wondering whether I should choose the fx-8120 (160€) and asrock 970 extreme4 (109€)
or go with intel i5 3570k (239€) and asrock z77 extreme4(159€). I don't have money coming out of my ears.
There isn't really a big difference between the i5 2500k and fx-8150 (basically a stock clocked 8120) from the benchmarks I've seen. I'm not afraid of overclocking either.
I currently own a 7870 (planning crossfire later)
corsair vengeance LP 1600mhz 2x4gb
silverstone 750w 80+ silver
A gaming machine that you are planning to Crossfire? i5-3570k or i5-2500k are much better options. The FX-81xx aren't well suited for gaming, they'll certainly game but their main strength comes from apps that use more than 4 threads (and even then their performance is sometimes spotty...). Games aren't there yet, and won't be for a while. I'd get a 3570k especially because you plan to Crossfire. It'd be worth it to me but whether it's worth it to you is relative to you and your situation.