question about old dell using rambus

hello all

my friend has a 1.3ghz p4 with 256mb of rambus (i assume pc800), and a 32mb geforce2 (bought computer in 2001).

for his 21st birthday his older bro who is also my friend enlisted me to choose upgrade parts (more ram, new video card), so i ordered 256mb more of pc800 from newegg, completely forgetting about how rambus has to be installed in pairs. they tried to install the 256mb with one of the 128 sticks he already had and it wouldn't work. did some research and i decided to come post here after i remembered that rambus has to be installed in pairs.

my question is about the memory size...the computer is a dell dimension 8100 that had 2x128mb of pc800 rambus. should the 256 module work with one of the 128's to make an effective 392mb? or do we need to get 256mb more for the first stick we ordered to work? i'm very inexperienced with rambus, obviously, and feel like quite an *** after my friend ordered this part and it didn't work like we thought it would.

any input would be much appreciated so i can get back with him on whether or not he needs to order another 256 stick.

thanks,

jeff

I think the sticks need to be the same size, not sure though.

The sticks need to be installed in matching pairs. Powerleap makes an adapter to use a socket 478 processor in the 423 motherboards. You can go up to a 2.6 400fsb processor.