The price difference says go with the Ivy bridge, unless... the ivy bridges motherboard is going to cost a lot more, also the ram speed shouldn't be a issue, I still game on DDR2, and have no FPS issues, also something too keep in mind is that all the FX processors you listed are Unlocked(very easy overclocking), where as all the Intel CPU within your price range are at there set limits and really can't be moved, so the AMDs can be easily pushed for a free performance gain, something not a lot of people factor in but the number one reason why below $200 AMD wins every time for me. In all Honesty all the CPU listed will game fine now and into the future, look at not only the price of the CPUS but factor in the price of the motherboards and ram aswell, then compare the complete package. One more thing to think about I have yet to run a game below 40 FPS on my system, which is getting dated on the CPU side by most peoples standards. The number one factor that helped me up my FPS, especially in new games was moving form dual 3870 x2's, too dual HD 6770, but kept my Phenom X3 8550 (small overclock to 2.5ghz), yet again only game I find my CPU limiting me is Planetside 2 and with that much scale can't really complain at all(specially since I am still getting 30 FPS in larger battles).
