Hello,
I purchased two 4850's last week and put them in crossfire. It was my first time using crossfire so i made sure everything was set up perfectly. I ran the crysis demo and it kept crashing with the error "atimkdag was stopped responding the drivers have recovered successfully".

Eventually I decided to take out one of the cards because this error happened continuously. Suddenly I relized the error went away and the performance without crossfire was even like 4 fps better on most of my games (demo's). When I tried putting back in the other card again it started display fuzzy images with numbers flying all over the screen in a very glitchy looking way. I tried many different things to try to fix the card but I just can't seem to get it to work. So I have decided to send it back to newegg for a replacement.

In the meantime though, I am worrying about what will happen when I get back a new 4850. I'll hook it up with crossfire bridges and it will do the same thing? Will my performance become worse than it is right now again? For now my games arn't crashing and i am gettin around 35-40 fps in lost planet demo with my non-defective card, not sure if that is very good or not for that game.
Please help.

Thanks,
Zman

CPU, Motherboard, Ram, PSU ?

Q9450, Intel P5E3 Wifi Deluxe, 2GB of OCZ DDR3 RAM, 600 watt PSU, and a 450 dedicated PSU to the cards.

is it a generic PSU supplying the cards?

What do u mean? Its called the juicebox and its 450 watts and i have two 6 pins coming out of it.

not enough power for the cards

check your "12v1, 12v2, 12v3, 12v4" on your power supply and tell us how many amps per rail

these cards need something like 30A of power each or they'll be unstable

generic meaning is it from a repitable company or some offbrand peice of junk.

Well if they weren't getting enough power there would be a red light and there isn't.

Looks like he has this:

http://tech.yahoo.com/ps/e-power-t [...] 1994810152

And that seems to have enough power.

Yup thats what I have. I don't think power is the problem.

Demos aren't the best tests for crossfire stability and performance. Shoot, I've had issues on the LOSt Planet demo on a couple machines. I'd try your cards out on a patched retail game of some kind before trying to diagnose crashing problems.

So did you try each card individually?

Your original post sounds like you only tried it with crossfire and with one card. And it sounds like you're assuming the other card is the problem. But did you try only the other card? Because there might be something that's just making crossfire weird that you need to fix. I'm just saying, test each card individually before sending one back.

Yes I tested both indivisually twice. Its that one card. Btw, the card I have right now is amazing its running the crysis demo at 30-40 fps and lost planet demo at 40-50. Why does crossfire make it worse?

Well if it's that one card that is the problem, then it might just do worse in crossfire because that card is holding your other one back. The cards need to communicate together, and the since the "broken" card doesn't really work that well, it's just wasting the resources.

When you get the new card, it should do better in crossfire.

Ok. I strongly believe that was the problem actually. The card was just defective. Thanks a lot yadge.

You're welcome. Feel free to come back if the problem persists after you get the new card. We might be able to help.