It's time to get rid of your boring screen saver and add some flair to your Mac. The one I like to use is the iTunes Artwork screen saver, which shows off all of your iTunes Artwork. and It's built right into your Mac.
1. Open System Preferences
2. Choose 'Desktop & Screensaver'.
3. Click on the Screensaver Tab and choose the iTunes Artwork Screensaver.
4. Select the options, and you can change how many rows of artwork you see & the delay time new ones cycle in.
Note: To keep the clock from showing on the screen saver, disable 'Show with clock'.
5. Click on the Test Button. If you like it, simply close System Prefs and it will be your new screen saver.