Sounds like incorrect settings in xorg.conf.
Try the following, after booting is complete:
- ctrl-option-F1 (should give you a command prompt)
- type: sudo nano /etc/X11/xorg.conf (return)
- make your edits (see below)
- ctrl-O (return) to write edited file
- ctrl-X to exit nano back to command line
- type: sudo /etc/init.d/kdm restart (return) to restart KDE
At the very least you'll need to modify "HorizSync" to 60-60 and "VertRefresh" to 75-117. Both are in the monitors section.
If you restart KDE and everything is in extreme slo-mo, you'll also need to edit xorg.conf to disable DRI (in the modules section, put a hash mark (#) at the beginning of the line containing "load dri").
Problem with the LiveCD is that you need to do this every boot. Hope you plan to do an install to the hard disk.