Ubuntu – How to disable hud-service

This CPU usage spike usually tends to come from programs that need to run periodically (like gwibber-service) to update something in the background. You should find any applications that are doing this (using system monitor/top it's easy to catch the culprit in action).

BTW it happens to me as well, and I was able to determine a few culprits: docky, my music player (banshee and rhythmbox are both rather bad behaved at times, but probably because of too many plugins), gwibber, and apt (looking for updates in the background). These may not be the cause of your problems, but you can try seeing if any are responsible.

To get latest drivers for the graphic card go to software center, edit(in the menu bar), software sources, additional drivers. You should find proprietary drivers for your GPU here.

Compiz usually doesn't use much cpu even if it's running on CPU. This may be caused by many programs opening at once, or there is some conflict between plugins. Restoring compiz to default setting should solve that. See here how to restore Compiz to default look here