Trip, if it's not a heat issue, check to see if they have "Soft Modded Drivers" for that card. I'll dig up the link when i find it and post it here.
Ok, looks like your card doesn't use "soft modded drivers" but here's a link to it anyway. This forum has knowledgeable people who will be able to help you.
http://forums.ocfaq.com/showthread.php?t=2755