according to these discussions there is a significant memory restriction for a jvm on a 32 bit windows systems.

http://forum.java.sun.com/thread.jsp?thread=272369&forum=37&message=1060964

http://forum.java.sun.com/thread.jsp?forum=37&thread=201718

Windows 2000 is a 32-bit operating system. This means that by default (Windows 2000 professional and Server), it can only support up to 4GB of memory (1/2 (2GB) for the operating system and 1/2 (2GB) for user applications). applications can use a special library called AWE (Address Windowing Extensions) to access more memory. For instance, windows 2000 advanced server (8 gig max), and windows 2000 data center (64 gig max) use AWE.