FYI:

Quite frequently we need to tell people to increase the maximum heap size using the -Xmx<somenumber>m argument in the bat file for MeV. People often ask (and I've wondered) exactly why the limit varies on machines that seem to have the same OS (same maximum addressable limits) and RAM and why a 2GB-RAM machine won't allow us to get closer to the 2GB addressable memory limit.   This little section of the HotSpot JRE faqs at least comes out and says that the limit falls between 1.4 and 1.6GB which is just what we've found empirically on 32-bit windows machines.  The page provides a few factors.

http://java.sun.com/docs/hotspot/HotSpotFAQ.html#gc_heap_32bit

John