Linux reconhece apenas memória parcial

Tentei diferentes distribuições linux (Ubuntu 12.10 Gnome Remix, Fedora 18, Bridge Linux) no meu novo laptop, mas todas elas têm um problema de memória. Meu laptop tem 4 GB de memória, mas o Ubuntu reconhece apenas 2,4 GB. Obviamente, o BIOS e o Windows 8 reconhecem todos os 4 GB.

Configuração do meu laptop: Lenovo B590 CPU: Intel Core i5-3210M Ram: Placa-mãe com chipset DDR3-SDRAM de 4 GB: Intel HM77 Express Placa gráfica integrada: HD Graphics 4000.

Pode ser possível que a memória perdida seja emprestada da Intel HD Graphics? se for verdade, sempre empresta memória máxima fixa ?!

Algumas saídas de comando úteis:

midecode --type memory

Array Handle: 0x000B
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: SODIMM
Set: None
Locator: ChannelB-DIMM0
Bank Locator: BANK 2
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MHz
Manufacturer: Hynix/Hyundai
Serial Number: 1A21B5B9
Asset Tag: 9876543210
Part Number: HMT351S6EFR8C-PB  
Rank: Unknown
Configured Clock Speed: 1600 MHz

Saída de free -m:

              total   used    free  shared    buffers     cached
Mem:          2483    1136    1346       0         56        515
-/+ buffers/cache:     563    1919
Swap:         4884       0    4884

Saída de cat /proc/meminfo | grep "Mem*"

MemTotal:        2542664 kB
MemFree:         1373552 kB

Saída de dmesg | grep -i memory

[    0.000000] initial memory mapped: [mem 0x00000000-0x1fffffff]
[    0.000000] Base memory trampoline at [ffff880000097000] 97000 size 24576
[    0.000000] init_memory_mapping: [mem 0x00000000-0x846f1fff]
[    0.000000] init_memory_mapping: [mem 0x100000000-0x11e5fffff]
[    0.000000] Early memory node ranges
[    0.000000] PM: Registered nosave memory: 000000000009d000 - 00000000000a0000
[    0.000000] PM: Registered nosave memory: 00000000000a0000 - 00000000000e0000
[    0.000000] PM: Registered nosave memory: 00000000000e0000 - 0000000000100000
[    0.000000] PM: Registered nosave memory: 0000000020000000 - 0000000020200000
[    0.000000] PM: Registered nosave memory: 0000000040004000 - 0000000040005000
[    0.000000] PM: Registered nosave memory: 00000000846f2000 - 00000000dae9f000
[    0.000000] PM: Registered nosave memory: 00000000dae9f000 - 00000000daf9f000
[    0.000000] PM: Registered nosave memory: 00000000daf9f000 - 00000000dafff000
[    0.000000] PM: Registered nosave memory: 00000000dafff000 - 00000000dfa00000
[    0.000000] PM: Registered nosave memory: 00000000dfa00000 - 00000000f8000000
[    0.000000] PM: Registered nosave memory: 00000000f8000000 - 00000000fc000000
[    0.000000] PM: Registered nosave memory: 00000000fc000000 - 00000000fe800000
[    0.000000] PM: Registered nosave memory: 00000000fe800000 - 00000000fe810000
[    0.000000] PM: Registered nosave memory: 00000000fe810000 - 00000000fec00000
[    0.000000] PM: Registered nosave memory: 00000000fec00000 - 00000000fec01000
[    0.000000] PM: Registered nosave memory: 00000000fec01000 - 00000000fed08000
[    0.000000] PM: Registered nosave memory: 00000000fed08000 - 00000000fed09000
[    0.000000] PM: Registered nosave memory: 00000000fed09000 - 00000000fed10000
[    0.000000] PM: Registered nosave memory: 00000000fed10000 - 00000000fed1a000
[    0.000000] PM: Registered nosave memory: 00000000fed1a000 - 00000000fed1c000
[    0.000000] PM: Registered nosave memory: 00000000fed1c000 - 00000000fed20000
[    0.000000] PM: Registered nosave memory: 00000000fed20000 - 00000000fee00000
[    0.000000] PM: Registered nosave memory: 00000000fee00000 - 00000000fee01000
[    0.000000] PM: Registered nosave memory: 00000000fee01000 - 00000000ffc20000
[    0.000000] PM: Registered nosave memory: 00000000ffc20000 - 0000000100000000
[    0.000000] Memory: 2515460k/4691968k available (6711k kernel code, 2027016k absent, 149492k reserved, 6459k data, 928k init)
[    0.000000] please try 'cgroup_disable=memory' option if you don't want memory cgroups
[    0.001851] Initializing cgroup subsys memory
[    0.522565] Freeing initrd memory: 23680k freed
[    1.430344] Freeing unused kernel memory: 928k freed
[    1.433360] Freeing unused kernel memory: 1472k freed
[    1.435653] Freeing unused kernel memory: 1124k freed
[    1.471316] pci 0000:00:00.0: >detected 65536K stolen memory
[   16.146844] Non-volatile memory driver v1.3

Linux antonio-Notebook 3.5.0-17-generic #28-Ubuntu SMP
Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

dmesg | grep BIOS-e820

[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009cfff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009d000-0x000000000009ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000001fffffff] usable
[    0.000000] BIOS-e820: [mem 0x0000000020000000-0x00000000201fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000020200000-0x0000000040003fff] usable
[    0.000000] BIOS-e820: [mem 0x0000000040004000-0x0000000040004fff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000040005000-0x00000000846f1fff] usable
[    0.000000] BIOS-e820: [mem 0x00000000846f2000-0x00000000dae9efff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000dae9f000-0x00000000daf9efff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x00000000daf9f000-0x00000000daffefff] ACPI data
[    0.000000] BIOS-e820: [mem 0x00000000dafff000-0x00000000df9fffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000f8000000-0x00000000fbffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fe800000-0x00000000fe80ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed08000-0x00000000fed08fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed10000-0x00000000fed19fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed1ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000ffc20000-0x00000000ffffffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000011e5fffff] usable