3 gb limit

[dhottinger at harrisonburg.k12.va.us]

I just finished install FC 6 on a Dell Poweredge 2950 with 2 dual core  
processors and 8 gb of RAM.  No problems.  Cleanest install in quite a  
while.  However, linux only sees 3 gb of memory.  free shows:
              total       used       free     shared    buffers     cached
Mem:       3369184    1381856    1987328          0     130380    1041488
-/+ buffers/cache:     209988    3159196
Swap:      2305316          0    2305316

On boot I see this:
kernel: 7269MB HIGHMEM available.
Jan  9 11:01:33 mail kernel: 727MB LOWMEM available.
So it looks like the kernel sees the memory, why doesnt it show up  
when I type the free command?
-- 
Dwayne Hottinger
Network Administrator
Harrisonburg City Public Schools