I've just upgraded my Debian Linux (Wheezy) to a 64 bit kernel, as well as user mode binaries, in an attempt to make use of the 4GB of memory in the system without PAE.Exchanging the kernel and packages seems to have gone fine, but I'm not getting the expected result:mymachine:~# dmesg | grep Memory[    0.000000] Memory: 2007644k/2062784k available (3494k kernel code, 452k absent,                       54688k reserved, 3042k data, 476k init)mymachine:~# uname -mx86_64What could be causing this? I would like to expand the memory further, but if I can't even make use of the current 4GB, that is a bit useless :)lshw output says shows the memory is properly installed: *-memory      description: System Memory      physical id: 29      slot: System board or motherboard      size: 4GiB    *-bank:0         description: DIMM DDR Synchronous 1333 MHz (0.8 ns)         product: PartNum0         vendor: Manufacturer0         physical id: 0         serial: SerNum0         slot: DIMM A1         size: 2GiB         width: 64 bits         clock: 1333MHz (0.8ns)    *-bank:1         description: DIMM DDR Synchronous 1333 MHz (0.8 ns)         product: PartNum1         vendor: Manufacturer1         physical id: 1         serial: SerNum1         slot: DIMM B1         size: 2GiB         width: 64 bits         clock: 1333MHz (0.8ns)The Memory Remap Feature is enabled in my BIOS.
Only two 2GB memory available on 64-bit Linux kernel
debian;64bit
Your motherboard apparently only supports 2GB or is buggy.  See the bios e820 section of the kernel boot messages for exactly what memory your bios is telling the kernel it has.