The more memory your computer has, the more programs you can run simultaneously, and the better performance you get from your computer. Increasing the amount of memory in your iMac is an easy way to improve performance.
How much memory is right for you?
* 512MB of memory is plenty to support most day-to-day tasks such as email, word processing, spreadsheets, web browsing, and using iLife '06 for basic tasks
* Choose 1GB of memory if you'll be photo editing, gaming, creating illustrations or building complex presentations. And if you'd like the flexibility of easily adding more memory in the future, keep a memory slot open by selecting the 1 SO-DIMM (rather than 2x512 SO-DIMMs) option.
* The 2GB option is ideal if you plan to use your system regularly for sound design, video editing, DVD authoring, animation and intensive gaming.