My recommendation is to do some research. Check your computer's motherboard manual. Find out the maximum amount of memory, and then how it is configured now. For example: I have two slots for memory in my computer. They are SDRAM modules. The total memory my motherboard can handle is 512MB. I had a couple 64MB SDRAMS, and bought a 256MB. I took out one 64MB module, and gave it to my wife. Her memory slots are full with 128MB, and she's very happy with that amount. Later when I bought another 256MB SDRAM, I yanked out the 64MB SDRAM. It's nice if you have more than one computer, because you can often use the leftover parts in another computer. I'm collecting almost enough parts to create a whole new computer! Ron