That depends on what Detail Level you use, low detail hardly takes up much where as high detail takes a little bit more memory to play, but either way this won't hardly effect your computer.
Approximate usage is 40-50 mb/h of playtime
One MB (megabyte) is equal to 1,024 kB (kilobytes).
If by game memory, you mean saves, I think that will be plenty (game saves are only a couple of KB). However, if it means you'll be playing homebrews or other, then 64 MB might not even hold one game. It's best if you invest in a multi-gigabyte one in that case.
130.84863 Megabyte.
101376 MB
476160 Mb
3.7 mb
1 mb is equal to how much
443.300283203125 MB
8,000 mb
0.1358 MB
2048 mb