Apenas 3GB de RAM com o kernel PAE em 12.04

Question

Eu instalei 4 GB de RAM no meu Thinkpad X60 executando o Ubuntu 12.04. Então eu instalei o kernel habilitado para PAE. Agora uname -r outputs

3.2.0-50-generic-pae

Minha CPU é capaz de PAE:

$ grep pae /proc/cpuinfo
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon bts aperfmperf pni monitor vmx est tm2 xtpr pdcm dtherm
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon bts aperfmperf pni monitor vmx est tm2 xtpr pdcm dtherm

BIOS relata 4096MB de RAM.

Ainda free outputs

             total       used       free     shared    buffers     cached
Mem:       3088452    2264192     824260          0     168056     852880
-/+ buffers/cache:    1243256    1845196
Swap:      2085884          0    2085884

O que há de errado?

Editar: Aqui está a seção e820 dmesg:

[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
[    0.000000]  BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000d2000 - 00000000000d4000 (reserved)
[    0.000000]  BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000bf6d0000 (usable)
[    0.000000]  BIOS-e820: 00000000bf6d0000 - 00000000bf6df000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000bf6df000 - 00000000bf700000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000bf700000 - 00000000c0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
[    0.000000]  BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
[    0.000000]  BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
[    0.000000]  BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000ff800000 - 0000000100000000 (reserved)

    

Answer 1

Acontece que provavelmente é um problema de placa-mãe / BIOS e não há solução alternativa. Semelhante a 64 bits e 32 bits 12.04 reportar menos 1 GB de memória RAM .