Please describe the problem:
The gnome-screensaver process will consume approximately 1 to 5% of the CPU while the mouse is being moved.  When the mouse movement stops but is within time limit the of the screensaver launching the cpu utilization goes to approximately zero.  An strace of the gnome-screensaver process shows show a lot of activity when the mouse is moved.

Steps to reproduce:
1. Launch Gnome's System Monitor or top
2. Move the mouse around the screen, watch the cpu usage by the gnome-screensaver process. 


Actual results:
Moving the mouse around should increased cpu utilization by the gnome-screensaver process.

Expected results:
Much less cpu utilization by a background process

Does this happen every time?
Yes.  More obvious on slower systems where the cpu utilization can be as high as 10% during mouse movement.

Other information:
It is observed on Fedora and Ubuntu distributions.

The process probably needs to be smarter about detecting movement.  Sampling every few seconds is probably a better approach.