[CentOS] Centos 5.2 and Xen

I have an 8 gig dram server I am playing with Xen on in centos 5.1 on right
now.

Are you telling us that Xen on centos 5.1 only uses 4 Gig Dram?

Or will it allow all 8 Gig to be used if setup correctly between main dom
and virt doms

 - rh