One of the things I’ve had to hunt for since my fresh install of Kubuntu is how to enable the proprietary drivers for my Nvidia graphics card. I don’t know if I installed something new to have it turn up, but if you have a fresh install of a KDE-based Linux distro and want to enable advanced driver you can either pull up Kicker (Alt-F2) and look for Hardware Drivers or you can go into the Kickoff menu and check for Applications > System > Hardware Drivers. Either way should let you launch the dialog to select any proprietary drivers available for hardware you have installed on your system.
Enable the drivers, reboot your system and you should have compositing enabled, which you can verify with System Settings > Desktop > Desktop Effects > General.
Of course I can’t guarantee that app will be available on other KDE-based Linux distros but that’s where I found it on Kubuntu 10.04 “Lucid Lynx”.
Now I’ll just need to figure out why Google Gadgets (Qt) have a visible border, even though I have compositing available.
