Comment 135 for bug 803943

Just to point out, compiz using a constant 5% of CPU time can only be considered "good" in comparison to compiz using a constant 10-20% CPU time. If there's nothing happening on the screen then compiz should be essentially completely idle and using much less than 1% of the CPU time, if any. A constant drain of 5% busy is a disaster for power savings, battery life, heat, etc., at the very least.

It's definitely possible for compiz to use essentially no resources when idle. That's how it used to work...