This has been occurring for as long as I have had openSUSE. It's oddly inconsistent as all of the following have happened:

1. It will load up with the screen looking fine, I open an application (any application) and suddenly the screen gets a little wavy and has flickers. No matter what I do with the monitor, it stays.

2. I will finally get a "lucky" day and have the monitor settings just right so there's no flickering and it's not wavy. The next time i start up those same settings now show as wavy/flickering.

3. I might be able to fix the waviness/flickering and then at some random point it just starts up again.

4. Occasionally, I can change the display settings in "Configure Desktop" and have it fix the issue (although not every time) but again, when I restart, it's back to the usual problems.

USING:
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OpenSUSE 11.0 (Although it happened with 10.3)
Linux 2.6.25.18-0.2-default i686 (It happened with previous release too)
4.1.3 (KDE 4.1.3) "release 63.3" (It happened with 4.0 as well)
ATI Mach64 GR
HP Pavilion f50 monitor
Display: 1024x768
Refresh 60 Hz (The only options it gives are 60, 70, 75 and none of those remains perfect every time. On the windows computer, it recommended 72, but that's not an option in "Configure Desktop"!)

Using the same monitor with a windows computer, it's fine every time I start that computer up.

Any ideas?