Crysis freezes & fizzles on Dual HD 4870

OK, I have been hammering forums for the last couple of days and am really getting nowhere. I just got Crysis and am trying to run it on a Dell XPS 630i: Core 2 quad 9550, 8GB RAM, dual HD 4870/crossfire. The game continually freezes or goes into ~.8 fps. I have tried all patches for Crysis, and just updated my vid drivers to 8.632 and catalyst 9.7. Tried removing keyboard and mouse (G15 and G9), rolling back Crysis to 1.1 and box stock, still freezes. Should I cut my losses and move on to another game? I had hoped that waiting a couple of years after a game has been out that most of this crap would be smoothed over. Help me, I'm a reformed console gamer and am getting frustrated here...

Call of Duty 2, Call of Duty 4, Oblibion, Fallout 3, and Bioshock all run great. Good framerates at high or very high settings. The PC is new, no factory crapware installed, and temps have all been good- when I can actually play Crysis for a few minutes before it freezes front sensor is around 75-80 and the rear is 90-95 F. Fans aren't even much beyond idle. PSU is Dell 750W and voltage readings are all good.

...I guess I don't know what 'fizzle' means - I wanted to use an f-word and that one was safe for posting. Anyway, I uninstalled, cleaned, and reinstalled; same result. I haven't tried rolling the ATI driver back a verison but I'm not really going to go in that direction for just one game.

It is only one game although that can be frustrating.

What about disabling crossfire what happens then?

What 4870 cards are these, and at what resolution are you trying to play and what game settings are you using ?