[{OF}Barney_B]

Let me start by saying I'm not an expert. Having said that, I've had the 9800 series card and I've got an X1950Pro now in an Antec 900 case. You're right on the wind tunnel comment. If the 9800 card had one weakness, it was the fan...either it just wasn't up to the task or was prone to failure. With my card, I more than likely damaged the fan when I blew the dust out of it; effectively forcing dust and debris into the bearings causing it to gum up and slow down. Unable to cool itself, it burnt itself out. It was damn near impossible to find a replacement fan so I went with Arctic Cooler for the win. That card is still kicking butt in one of my 'puters. Now off to the the 1900. Same deal here as you can hurt the fan by a misdirected air blast and all that shielding can trap dust, hair and lint in it making it worthless. Also you can actually blast the heatsink paste out from between the heatsink and video chip if you're not careful. I'd just take a look at the fan as it runs and see if it is slowing down or not running at full potential. I'm not sure if you can get an aftermarket cooling setup for this card...not that I think it unlikely, I've just not looked for one. If you've got a pet or some other sort of hairy beast in the vicinity of your 'puter, remember that the Antec 900 is the next best thing to an air filter/vacuum cleaner you can get without buying one.

Here's what I'd do to help sort it out.
Carefully check the card for dust and clean it up, if you have to take it out do so.
Check to make sure the fan is up to the task and that it's working properly.
Make sure you don't have cables blocking those wonderful 120s from doing their job.
Consider putting the additional 120 on the sidepanel (there were several versions of the Antec 900 and mine didn't come with the sidepanel fan although the mount for it was there).
Aftermarket cooling-check with Arctic Cooling. They seem to have their poop in a group.
If the card does check out ok after all is said and done, perhaps Crysis is just too much for the 1900 series of cards. I understand that this game is a gut ripper on hardware but I'll know more about that once I get the game myself. In the end you might just have to get a newer card that can handle the demands placed upon it...sorry to say.

One other thing, in "my" experience, I'd turn off the Catalyst overclocking thingee and run it at stock speeds. I tried it out once for g-whiz and it raised the temperature of the card to what I'd consider scary levels. You could of course beat it to death and send it back in for warranty replacement. Not sure how that works.

Check out the easy stuff and wait for Chem to chime in. He's got alot more "know-how" than I.