Possible ATI Issue

I'm at work currently, so can't post my dxdiag right now. I'll pastebin it later tonight if I remember.

Win7 64bit
i7 920
ATI 4850 x2 512MB (I'm about 1-2 drivers behind current I believe)

Currently, this problem is only in online games. With crossfire enabled at 1280x1024, maxed settings, with VSync enabled I will start online rounds running great (though I can see textures loading in over about 2 seconds starting with very low textures and then being replaced by high textures). However, about 2-5 minutes into each game I get a slide show (sometimes as bad as 1-2 frames every 8 seconds or so) and the textures seem to load in slower and slower. This also corresponds to menus becoming fairly unrepsonsive if I hit escape while the match is ongoing (and especially the video options menu). If I drop down to default settings all the problems go away. If I disable crossfire I can run without issues at the tick between default and high, though I get a little bit of tearing here and there.

In single player the game runs flawlessly both in crossfire and non-crossfire on all max settings for extended amounts of time (i.e. up to 60 rounds on one of the unlimited wave blitz games).

A couple of my friends using crossfire have experienced the same problem.