Machine has 2 RAM slots; 1 gig capacity each. Presently has (2) 256 mb sticks (2100 ddr/266mhz/184 pin). I want to take out both, and replace them with (1) gig stick to put in one slot/leaving a slot empty. Is it ok to leave one slot empty as opposed to (2) 512's? Does it matter which slot to have just one stick? Is there a "master slot" of the two? P.S. Is it ok to put generic RAM in a Compaq machine - or does it have to be Compaq brand RAM? Thanks...

Did you check to make sure your Compaq can take 1GB sticks of memory? Does your board support dual channel mode? If it does, it would be better to install a matching pair of RAM sticks. If it only supports single channel mode, why not just swap out one stick of RAM & keep the other 256MB stick in place? That way you'd have 1.25GB of memory. "Is it ok to put generic RAM in a Compaq machine" Why would you buy generic RAM when there are so many name brand RAM manufacturers (Crucial, Corsair, Kingston, Muskin, to name a few)? The 1st thing you should do is enter the info about your Compaq into the "memory advisor tool" at Crucial.com....or you can run the "system scanner tool". Then you'll know exactly the type & amount of RAM your system supports. http://www.crucial.com/

Thanks for the crucial link/reply... The machine has a "maximum of 2 gig RAM" ..and there are only 2 slots... So it must support "1 gig" sticks. Yeh, it's DIMM/dual. The reason I don't want to keep one 256mb stick in is that the general consensus advises not to; that it may slow down machine. It will probably be two different brands, anyway. So...is it okay to keep one in and does it matter which slot I choose as the one? I don't really want to load up this machine too much - it's kind of outdated - not worth buying 2 gigs.

If the computer came with PC2100 RAM anything you buy today may have higher density chips than the memory controller can handle. Do as jam states and when you see the recommended RAM write down ALL the specs, not just the module size. Post back for further help.

Each slot should be numbered. Generally this is in small print, nearby on the mobo. It was my understanding they should be populated in order. i.e. 1 first, then 2 and so on. Good Luck - Keep us posted.