AMD Video Card Issues

As has been said in some of my previous posts, I was lucky enough to enjoy Rift during the beta. Unfortunately, during that time there were huge AMD issues with video cards overheating and basically dropping the machine to a black screen - requiring a hard reboot to become functional again.

I recently resubscribed and although I no longer require a hard reboot, there are times where my game will pause for 5-10 seconds, drops to a black screen shortly, then the game re-draws and becomes active again.

I'm currently running a Radeon HD 4600-series card - albeit not the best at all - but I have the graphics settings completely turned down to the lowest they can possibly go. Sitting on an AMD Phenom X4 and 4GB RAM.

Has anyone else experienced this issue? Any quick tips to solve the problem before I drop the money on a better video card? I'd love to upgrade but building my girlfriend a gaming rig for Christmas and went for the Radeon HD 6870 for her, will be a few weeks before I have spare change to upgrade myself. Anything I can do in the interim?