My Empeg originally was the top spec model with 2x 18GB drives (and £1500!) and I had heard before that the issue was down to only having 12meg of RAM installed to actually address it all being the problem, and I agree it's quite a marvelous achievement in itself to be running as well as it is, I'm sure an M$ product wouldn't be, however I thought that was a memory problem for a single playlist and not the entire collection.
Is there a way for instance to cheat the RAM allocation using disk cache as there is plenty of space available?