CPU limits on the different versions of RHEL?

[David Miller]

In the product comparison on the Red Hat site they have some hardware  
and software limits listed for each version of RHEL. For RHEL4 & 5  
workstation they have a Physical CPU limit of two. Yet I have a Dell  
Poweredge 6800 and a 6600 with four physical Intel xeons 
(hyperthreading on each CPU) running RHEL4.x WS just fine. Top and / 
proc/cpuinfo show all eight cores. Why do they list these limits if  
they don't really exist?

http://www.redhat.com/rhel/compare/#desktop