I posted the prices, the 8320 + mobo + 212 evo comes out to $242. The i5 4460 + mobo comes out to $247. Neither motherboard is really over the top, both are in the same tier for their builds so it's not comparing a premium board to a junk one. The mobo's come out to almost identical prices, the only cost difference is in the cpu's. It's a $32 difference between the 4460 and fx 8320. Factor a decent cooler like the 212 evo and there went the cost savings. An 8320 stock will definitely lag behind the 4460, a 212 evo and that 970 mobo should allow some overclocking of the 8320 which will get it closer to the i5 in performance.
As I said in some games there won't be much difference - for those games even a $106 i3 will suffice with a decent gpu. But in the games where the cpu does matter the i5 will outperform the 8320 at the same price. There's no pricing voodoo going on, the fx performs between the i3 and i5 and it's priced accordingly.