DIMM is Dual Inline Memmory Moduel.... of which all DDR is [I am 90% sure on that] DDR is DDR, just make sure its not DDR2 [which is really new so its probably not]. So the stuff on sale should physically fit into your machine. The only thing you have to watch out for is the speed. If the speed of the memory on sale is equal too or higher than your current RAM you will be fine. [examp: DDR 266 DDR 333; DDR 400; if you have DDR 333 in your computer, either DDR 333 or DDR400 will work fine, but DDR 266 will not]
Does that help?
EDIT: if you know the make and model number of your computer you should be able to go to www.crucial.com and look up the make and model and get the specific types of ram that go in your machine.
Edited, Thu Nov 11 11:56:15 2004 by BrightMorn