I've been frustrated trying to get AMD hardware to run this game. Though the only hardware I've tried has been really cheap. Some people still say that the absolute HIGHEST AMD processors won't run this game well. Now they're definition of well is probably this "60+ fps in 500+ user battle." If you want to be able to play in big battles then I believe the only choice is Intel. Just to put these frame rates into perspective, all YouTube videos run at 30 FPS(not 60). Simply go watch a YouTube video and you'll see that 30 FPS is quite smooth. Most people say that they get around 40 FPS in big battles with an Intel processor. If you've been dealing with 0.1 - 1 FPS in these situations like I have then you can obviously see why I say "lol what?!" when people say they "struggle" to get 40. I understand that you want a monitor, harddrive, mouse, and keyboard for this setup to go with the performance parts, but I can show you the rig I'm going to build in a few months:
I just bought a radeon 7750 a few months ago and I plan to salvage it from my old setup to build this new one. Also DO NOT get a super expensive video card unless you need it for obvious reasons(120hz monitor, multiple monitors). I haven't tried this GPU with no CPU blockage, but I predict the result will be pretty good. I've ran this game on high(possibly ultra, can't remember) with this card. If you want I could go turn the game to ultra(besides textures, that's RAM not GPU intensive). Then report the frame rates when I have no CPU blockage(i.e. an empty facility on Amerish). A got this card for about $90 on ebay so it's defenitely something to consider. If you want an nVidia card(which I would recommend if you got the money) then go for the gtx 660. It should be able to run the game on ultra with the extra particle effects that you can get from nVidia cards in this game. Though to be honest, unless you spend $2000 for 2 GTX Titans then you won't be able to run this game on absolute maximum graphics. The shadows simply take too much power for any reasonable setup to run. Though the game should look pretty awesome with a gtx 660. Given this is all speculation. Though I seem to recall some youtuber having the gtx 660 and it running the game quite fast and good looking.