Intel SR1500AL doesn't see 4 GB

[Rihad]

Hi,

I'm attempting to install FreeBSD 6.2 on Intel Server System SR1500AL 
with 4 gigs ram and CPU: Intel(R) Xeon(R) CPU            5130  @ 2.00GHz 
(2002.99-MHz 686-class CPU). The install goes OK, but FreeBSD doesn't 
recognize that there's 4 gigs of ram unless I rebuild the kernel with 
PAE enabled; it sees only ~2.5 gb otherwise. And there's a suspicious 
white line emmited during boot: like "1.5 gigs above 4 were ignored". 
What's up with that? As I'm new to high-end hardware, am I using the 
right FreeBSD build of i386? Why can't it see 4 gigs without PAE?

Thanks a lot.