PC freeze/GFX stopped responding

Hi all, im having a big problem playing RIFT.
Every time a planar tear comes into view (looks like this http://www.little-players.com/blog/wp-content/uploads/2011/01/rift-tear.jpg) my pc will lock up, screen will go black, flicker, audio stutter, then go back to the game. At this time there is a popup in bottom right saying graphics driver stopped responding and recovered.
This only happens whenever one of these planar tears come into view of my screen.

Im running a radeon hd4670, and i have tried old drivers, new drivers, windows updates, motherboard driver update, i just dont know why its happening or what i can do to fix it.

Has anyone else had this or does anyone know why this is happening to me?

Thanks in advance

I had this problem with my NV9500GT, If i remember correctly i had to use forceware drivers, which were a pain in the backside just to find. Eventually i found some that worked ok, Before you try that check all of your 3d gaming settings(in windows) & ingame settings. also give sisoft sandra a try that can be helpful

if all else fails try driver doctor (a free version of driver detective)

Also what Screen Resoloution are you running at ? ;Have you tried a different one ?
Has it always done this and do any other games do this ?

it seemed to be AMD Vision control venter, because i uninstalled that and it hasnt done it since, but when i re-install it, i get the not responding issues.

Does anyone know what this could be?