<A target="_blank" href="http://blog.nashcom.de/nashcomblog.nsf/dx/shared-memory-size-by-default-limited-to-2gb-in-domino-32bit-on-win64.htm">Daniel Nashed found his Windows 64bit server</A> failed to allocate more than 2GB to Domino so he did some research. There is a Notes.ini parameter you can use to increase the memory allocated to Domino.