amd64 does not see all 4 GB RAM on tyan GT24

[Claus Guttesen]

Hi.

Just received a Tyan GT24 with a S2891 board. In the
bios-setup-utility the board has 4 GB RAM, but when FreeBSD 6.0
release boot it only recognizes 3 GB. Dmesg:

Copyright (c) 1992-2005 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD 6.0-RELEASE #0: Mon Nov  7 16:30:28 CET 2005
    claus at ulla.eurofoto.no:/usr/obj/usr/src/sys/WEBSRV
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Dual Core AMD Opteron(tm) Processor 275 (2210.20-MHz K8-class CPU)
  Origin = "AuthenticAMD"  Id = 0x20f12  Stepping = 2
  Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT>
  Features2=0x1<SSE3>
  AMD Features=0xe2500800<SYSCALL,NX,MMX+,<b25>,LM,3DNow+,3DNow>
  Hyperthreading: 2 logical CPUs
real memory  = 3488743424 (3327 MB)
avail memory = 3368710144 (3212 MB)
ACPI APIC Table: <PTLTD          APIC  >
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
 cpu2 (AP): APIC ID:  2
 cpu3 (AP): APIC ID:  3
ioapic0 <Version 1.1> irqs 0-23 on motherboard
ioapic1 <Version 1.1> irqs 24-27 on motherboard
ioapic2 <Version 1.1> irqs 28-31 on motherboard
acpi0: <PTLTD   RSDT> on motherboard
....

I have tried to switch between Linux and other in OS mode from within
bios, but no difference.

regards
Claus