4Gb memory?

Hi, I just installed 4GB memory to my system. In BIOS it shows up all 8x512M chips. But after boot it shows:

$ free
            total       used       free     shared    buffers     cached
Mem:       3753328     566800    3186528          0      96040     189960
-/+ buffers/cache:     280800    3472528
Swap:      2096440          0    2096440

$dmesg
Linux version 2.4.22 (root) (gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #1 SMP Mon Oct 27 12:44:16 EST 2003 BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000007ff77000 (usable)
BIOS-e820: 000000007ff77000 - 000000007ff79000 (ACPI NVS)
BIOS-e820: 000000007ff79000 - 00000000e7f77000 (usable)
BIOS-e820: 00000000e7f79000 - 00000000e8000000 (reserved)
BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
user-defined physical RAM map:
user: 0000000000000000 - 00000000000a0000 (usable)
user: 00000000000f0000 - 0000000000100000 (reserved)
user: 0000000000100000 - 000000007ff77000 (usable)
user: 000000007ff77000 - 000000007ff79000 (ACPI NVS)
user: 000000007ff79000 - 00000000e7f77000 (usable)
user: 00000000e7f79000 - 00000000e8000000 (reserved)
user: 00000000fec00000 - 00000000fec10000 (reserved)
user: 00000000fee00000 - 00000000fee10000 (reserved)
user: 00000000ffb00000 - 0000000100000000 (reserved)
2815MB HIGHMEM available.
896MB LOWMEM available.

$ cat /proc/meminfo
       total:    used:    free:  shared: buffers:  cached:
Mem:  3843407872 580702208 3262705664        0 98418688 194662400
Swap: 2146754560        0 2146754560
MemTotal:      3753328 kB
MemFree:       3186236 kB
MemShared:           0 kB
Buffers:         96112 kB
Cached:         190100 kB
SwapCached:          0 kB
Active:         117228 kB
Inactive:       264336 kB
HighTotal:     2883028 kB
HighFree:      2595896 kB
LowTotal:       870300 kB
LowFree:        590340 kB
SwapTotal:     2096440 kB
SwapFree:      2096440 kB

Does this look right? why it is 375328 KB instead of 4294967296 kB? I compiled with 4GB mem. I did try 64GB version but after boot I got "pc_keyb jammed" message and could not use keyboard at all.

Also I have another problem. My harddrive is: hda: WDC WD1200JB-75CRA0, ATA DISK drive, hdparm -i /dev/hda
/dev/hda:

Model=WDC WD1200JB-75CRA0, FwRev=16.06V16, SerialNo=WD-WMA8C2065737 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq } RawCHS=16383/16/63, TrkSize=57600, SectSize=600, ECCbytes=40 BuffType=DualPortCache, BuffSize=8192kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=234375000 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}

PIO modes:  pio0 pio1 pio2 pio3 pio4
DMA modes:  mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5

AdvancedPM=no WriteCache=enabled
Drive conforms to: device does not report version: 1 2 3 4 5

If I idle the machine for a period of time (say over weekend), then on screen it says:
dma_timer_expiry
dma status == 0x21
hda: error waiting for DMA
Then the machine completely freeze. Is that some bug already known? Thanks!

_________________________________________________________________
Want to check if your PC is virus-infected? Get a FREE computer virus scan online from McAfee. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963

Which motherboard? Some boards will reserve some of the area between ~3.7 and 4G for various option roms and other devices present in the system. Resulting in "lost" physical RAM.