Upgraded to a EVGA GTX570 SC from a GTX285 and noticed a big improvement! Beta 4 improved my FPS as well; getting over 100FPS over medium water and 50FPS in town. Watching my TRACK is a constant 60FPS. It was damn near unplayable in combat with the GTX285 on the first couple betas. Can't wait for TrackIR to get their sh*t together so I can use it. So I would say the best way to improve FPS is to dump that 2 year old or older vid card and wait for the final release. I am not a big fan of SLI as I don't believe anyone should have to shell out twice the amount just to make things work; also not to mention the EXTRA power requirements--what a JOKE.
1156 ASUS i7 870 stock
8 RAM
GTX 570 SC