Section 39.1 of the System Administraton Guide for RHEL 3 correctly notes that kernel-hugemem uses the 4G/4G split but incorrectly claims the maximum memory it supports on x86 is 16 GB. It likewise incorrectly claims that the maximum memory supported by kernel-smp on x86 is 64 GB. This should be the other way around: kernel-smp maximum at 16 GB and kernel-hugemem maximum at 64 GB.
Thanks a bunch Steve! The documentation team appreciates your efforts! Please watch for this to be updated for the Web release of the SAG (system admin guide) for RHEL4 in Feb. 05! :-) Andrius.