Has X changed? Screen Flicker Problems

[Robert Tilley]

When I returned to my Kubuntu box yesterday morning, my screen was
 stuttering. Every second the screen would flicker.  A shift by only a few
 pixels would cascade down the sides of my LCD screen.

My windows install on my new Windows box is rock-solid and stable, so the
point of trouble is not my LCD monitor.  (Dell, good quality.)

Have there been any changes to Xorg lately that could have introduced this
change?  Before, during a Kubuntu install, everything would be stable and
now, even booting off the install CD for a fresh install, my screen in Linux
is unstable.

Perhaps some hardware gurus know something I don't.

Thanks, Bob