A64 3200 comes in two sockets (and several core revisions).
For that matter, memory has many more attributes than just size, but it's not as critical to the motherboard selection as the above two. I'm assuming of course that you have some variety of 2x512 PC3200 that's reasonably compatable. Memory selection is another matter entirely if you haven't bought yours yet.
MSI makes good motherboards that will handle any combination of the above.
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