I'm having a problem with wavy video.

I'm running 9.10 64bit. EVGA motherboard with a Core i3 with built in i915 video. When viewing the bios screen, grub and the initial loading screen it's fine. Then the resolution switches (I'm assuming) to the default for the monitor and it goes all wavy and flickery.

I does it in gnome no matter what resolution or refresh rate I use. I seem to recall it was fine way back when I did the initial install of 9.10 from the CD, then I did the big after install upgrade and it seems to have started doing this. I know it's not the monitor or cable as I've tried two others and it does the same thing

Any ideaers?

Thanks.