RAM deals
iMac, Mac OS X (10.5.1), 2GB RAM memory, 2.0 GHZ core duo processor, 250GB hard drive
iMac, Mac OS X (10.5.1), 2GB RAM memory, 2.0 GHZ core duo processor, 250GB hard drive
Your iMac can take up to 2gb in each slot, but can only handle up to 3gb total. It came with each slot having 512mb in it, so these will have to be removed and sold or trashed.
You could put a 2gb chip on one side and leave a 512mb in the other for a total of 2.5gb. Many people will tell you to use only matched pairs, which has a slight benefit, but the greater benefit is from having more RAM overall!
Or, you could put 1gb on one side and 2gb on the other side for a total of 3gb. You decide.
Here is a link to a page with your iMac's specifications: http://www.everymac.com/systems/apple/imac/stats/imac-core-2-duo-2.16-20-inch-sp ecs.html
Here is another one that explains why 3gb is the maximum RAM for your system: http://www.memory-up.com/Memory/AppleiMac14834.html
RAM deals