Memcached Server - Memory Consumption

I was just testing the memcache server on a Windows box and had set it
up as a Windows Service and to my surprise (or my shock really) it was
using 47+ meg of ram with no data even loaded in it yet. Has anyone
else used the Windows port of memcached for their Rails projects and if
so how much ram was it using?

You don't say what version.

Does memcached use less memory on Mac OS X or Linux than Windows?

There's an entire mailing list devoted to memcached. You should ask your question there. The author of the win32 port even reads it.