Originally Posted by Von Manteuffel

Hello, Lioneye - and welcome to the best game community in the world.

I'm running a very similar system to yours on my desk-top under XP and on my lap top under Vista ( except on the lap-top I only have one 7900GTX.) I've not experienced problems with either. The desktop is running a 21" iiyama at 1680 x 1050 and the Dell XPS laptop is running at 1900 x 1200 - both without problems.

It does sound like a driver problem. Have you made sure you're not running anything else in the background, have minimised the processes which are running and have turned anti-virus software off?