Help With RAM

My mother's old Compaq Presario (I think she bought it around 1999) needs a RAM upgrade to handle the games she plays at "POGO ". Just popped the case and she currently has 64MB, PC100 SDRAM. Question....I have 256MB, PC133 left over from upgrading one of my old pc's. Will that work???

 

Yes.

The PC most likely will only take advantage of PC100 rated RAM, but PC133 is backward compatible. A total of 320 would be preferable than only using the 256 stick. Only small issue to watch for is if the machine runs better with only the 256 stick. This would indicate that the 256 is better quality than the 64. Unless you experiment you probably won't notice much (or anything), so try both sticks.
If the machine is rated for PC133 then you wouldn't use the 64 as the system will run at the lower speed. For a 1999 vintage machine this is unlikely. But a check of the model specs will confirm, if you can be bothered. I doubt Compaq would have used lower than rated RAM.

 

Theoretically, Paul comments are right on, however, what should be and what is can often be quite different. If the PC133 is high density and your mom's presario requires low density - it ain't gonna work. What I've found in a lot of older systems that ran on PC100 is that they run very poorly if at all with PC133, even though SDRAM is technically backwards compatable. If you have a 16 chip 32x64 256 MB stick, you'll probably be Ok but if its an 8 chip stick, I doubt that you will experience anything but problems.