Asus A8V Deluxe Can't see full 4GB

Hey Guys..

Disclaimer:
I've googled the list... and didn't see anything...

I've got a guy running an Asus A8V Deluxe w/Ath64 3000+ and 4 sticks of 1GB 
and his setup (with either RH-EL3 64bit or RH-EL4 64bit) seems to be 
exhibiting the classic x86/32bit problem of not being able to map the memory 
around the 512MB PCI memory/chipset mapping.  I'm not sure about the 2.4 
kernel, but I would think that the 2.6 64bit kernel (or the motherboard) 
could map that memory high (beyond the 32 bit range) to access all 4GB, but 
nothing stands out on how I should go about doing this (BIOS seems void of 
any such "settings", and I know of no OS/kernel (sysctl) parameters that can 
do this).  

And no.. Running PAE is NOT desireable.. This is a 64bit system.. why can't I 
either map-high, or around the PCI hardware limitation?! (and NO.. I don't 
want to add another 1GB to "get around it").  This guys wants 4GB.. Not pay 
for 5 get 4.5.

Am I missing something here... or is this system simply NOT going to be able 
to get to that last PCI mapped 512MB?

Anyone?

Tweeks