[QUOTE=adict2jane;2154272]http://support.dell.com/support/edocs/systems/dim3100/en/sm/parts0.htm#wp1043338
This is the manual for the computer. Isn’t really helpful at all. Just says that your computer uses DDR2 memory and that mixed memory will run at the slowest stick speeds. But you should be able to use any speed DDR2 memory, PC4200, PC6400, etc.
If you do get any of the memory kits from newegg.com or anywhere else, just make sure that the sticks are rated at 1.8 Volts.
Hope I was helpful :)[/QUOTE]
Not quite. The trouble with that recommendation is that a lot of PC2-6400 memory has an SPD (Serial Presence Detect) chip that knows only its rated speed - and nothing slower. And a lot of Corsair-branded PC2-6400 memory has an SPD chip whose only data slower than the rated speed is a nonstandard PC2-4320 speed. Most name-brand (OEM) systems require an SPD which has valid data for exactly the memory speeds that are officially supported by that system. I tried a PC2-6400 module on a name-brand system which supported only up to PC2-5300 memory, and the system wouldn’t even POST at all (and the OEM system offers no provision at all whatsoever to manually set anything). The SPD-programmed speeds must EXACTLY match those memory speeds which are officially supported by the system or else the system will not even POST!