Why the Openfire can not be started when memory more than 1920

My Openfire is 3.6.3.

My Linux server has memory: 3600MB,

Today I want to increase the Openfire memory to 2048M, so I edit the /etc/sysconfig/openfire:

 **OPENFIRE_OPTS="-Xms512m -Xmx2048m"**

Then restart Openfire server failed.

OPENFIRE_OPTS="-Xms512m -Xmx1792m"

Who can tell me what is problem and how to clear it.

Thanks

But when I modify the configure as 1792m, Openfire started ok.

This is a limit of 32-bit JVM, not Openfire. So, if you want to use more, use 64-bit OS and 64-bit JVM. JVM - Java Vistual Machine.