Glxgears крутит нормально. Кеды не могут работать в режиме opengl.
Desktop effects are not available on this system due to the following technical issues: OpenGL compositing (the default) has crashed KWin in the past. This was most likely due to a driver bug. If you think that you have meanwhile upgraded to a stable driver, you can reset this protection but be aware that this might result in an immediate crash! Alternatively, you might want to use the XRender backend instead.