Not that this answers your question but what version are you running, how large is your data file, and how much RAM is on the server? FYI, the 7.0.2 release notes indicate a fix that improves memory management.
I am running version 7. My data set is not too large, only a couple million rows. I am running this "in the cloud" on a virtual server with 2 gigs of RAM and nothing else running on it.