From Mandriva Community Wiki

[edit] Enabling Translucency/Drop Shadows to KDE

[edit] Editing the Xorg Config File

The Xorg that ships with Mandriva 2006.0 is capable of using hardware 3d acceleration to render translucency effects and drop shadows which can easily be controlled within KDE.

Note: The facility is still experimental and not entirely reliable so proceed at your own risk!

It is recommended that you have at least the following hardware for a reasonable experience:

• Nvidia/ATI 3d graphics card with at least 128MB memory
• Intel Pentium 4/Celeron 2GHz / AMD Athlon 2200+
• 512MB RAM

Before beginning ensure that you have the latest 3d drivers for your card, open up a console and run glxgears, if the output is less than 200fps I wouldn't bother. To begin open a console and login as root, the vi /etc/X11/xorg.conf and add the following lines (Beginning or end - it doesn't matter).

 Section "Extensions"
     Option "Composite" "true"
 EndSection

It is recommended that you restart X at this point to make sure all went well, run xdpyinfo and make sure it is displayed.

[edit] Setting up KDE to use Translucency/Dropshadows

If all went well the next part is fairly easy, go to star menu->System->Configuration->Configure your desktop, select System->Window Behaviour and choose the Translucency tab. Check "Use translucency/shadows" and click apply. You will now need to log out and back in for the new settings to take effect.

In the window behaviour/translucency screen you can alter a number of settings, play around until you find the settings that provide the best performance for you. It is recommended that you don't mix drop shadows with translucent windows unless you have a top of the line computer.