Last night I was playing around with Desktop Effects and set the composting engine to Xrender, it was openGL. And things started to slow down tremendously. There is now lag on Alt+F1, lag when mousing over hidden taskbar, lag when moving windows, etc. I was trying to get rid of a trail of images when moving windows around. I created more problems.
Things got even better when I tried to change back to openGL:
“Failed to activate desktop effects using the given configuration options. Setting will be reverted back to previous values. Check your X configuration. You may also consider changing advancde options, especially changing the composting type.”
The same thing happens when I click on “Default”, the default options disable desktop effects.