I have SDRAM, DDR1, DDR2?

[Edward.H]

I have two desktops, both of which are old and need memory upgrades. One of them has 1GB of memory and I want to upgrade it to 2 or 3, and the other is a real fossil and has 128 MB of memory. I am hoping that both are DDR1 because then I could take the 1GB chip from the one computer and use it in the other. They are from 2001 and 2003 respectively I believe. How do I tell which kinds of memory each computer has and which kinds each is compatible with, preferably without opening the boxes?

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