Try with one video card?
When you mean stuck, you mean ATi crashes or that they suck (as in the FPS is low)? Comp crash?
With Xfire, make sure you're using the right game profile.
Could be a driver issue. Have you tried the 11.1a hotfix drivers?
Oh what version of ATi drivers are you using?
When I had the 5770, I tried Xfiring a friend's 5770 and never could get them right.
Also if he's playing Counter-strike, Xfire might be a bit of overkill with the trade off of stability.