Installing more RAM can be one of the best things you can do to improve the performance of your iMac. The system software will run faster and you will be able to have more applications running at the same time. If you are still using OS 9 or less, you can allocate more RAM to individual applications which will make them run faster and be more stable. You can also turn off Virtual Memory. Virtual Memory uses the hard drive to store data when all the RAM is used up. This is great when you don't have much RAM but accessing this data is very slow compared to accessing it from the RAM, hence it slows down your computer. How much Ram to add is up to you. You can have up to 512mb.

Perhaps the hardest thing about this upgrade is making sure you purchase the correct RAM modules for your iMac. On the next page you will find the names of the modules you need to look for and a brief description of the different types and sizes of RAM.