top shows only half of realmem?

[Bartosz Stec]

Guys,

could someone explain me this?

    # sysctl hw.realmem
    hw.realmem: 2139029504

top line shows:

    Mem: 32M Active, 35M Inact, 899M Wired, 8392K Cache, 199M Buf, 58M Free

32+35+899+8+199+58 = 1231MB

Shouldn't that sum to all available ram? Or maybe I'm reading it wrong? 
This machine has indeed 2GB of ram on board and showed in BIOS.
i386  FreeBSD 8.2-PRERELEASE #16: Mon Jan 17 22:28:53 CET 2011
Cheers.

-- 
Bartosz Stec