What can i do when my iMac gets slow?

Question

the hard disk is used by 4 different users. After some time the computer is getting very slow. What can i do to speed up the performance again?

Answer 1

With 4 users, check the hard disk to see if it's getting full.

Typically hard drives need at least 25% free space just to operate properly. So, a 60 GB drive should have no more than 45 GB of used space.

Each user should be making copies of Folders of photos, movies and music to CD or DVD, and then delete as many of these types of Files (not the Folders) as possible.

TIP: Each user should Log Off when not on the PC, OS X will continue to do things like updating RSS feeds and downloading Podcasts, etc. even when the other user is away.