Very Computer

I have an iBook2 500 with Ati Rage M3 running debian.
Whenever i try to use the vga-out under X there are two possibilities:

- The screen is moving in horizontal waves (connect to running iBook)
- The screen is cut into pieces and these are laid on each other
  (very ugly) (connect when it is running)

The Console is ok on external monitor.

I use an BenH 2.4.20-pre11-ben0 kernel and Xfree 4.2.1. I'm using
aty128fb.
Perhaps you have some tips for me. Everything I have read till now had no
effect.
Thanks for any advice.

entenhausen