Red Hat Enterprise Linux 3 virtual machines do not detect more than 4GB of memory (630279)
The Athlon kernel that is shipped with Red Hat Enterprise Linux 3 does not support Physical Address Extension (PAE). As a result, virtual machines running Red Hat Enterprise Linux 3 on AMD hardware might not detect all the memory available to them. This occurs when the memory allocated exceeds 4GB.
Red Hat Enterprise Linux 3 virtual machines do not detect memory more than 4GB.
This is a known third-party issue with Red Hat Enterprise Linux 3. For more information, including current information on possible solutions, see http://kbase.redhat.com/faq/docs/DOC-7002.
Note that hugemem kernels are sometimes listed as a possible solution to this issue, but VMware does not support hugemem kernels, as described in http://kb.vmware.com/kb/8964517.