Ubuntu 12.04 LTS 32bit 未检测到 4Gb ram

Question

我最近为现有的 12.04 32 位 Ubuntu 安装了 4Gb 内存。它没有被识别，只有 3.2Gb 显示，请参阅：

administrator@Root2:~$ free
             total       used       free     shared    buffers     cached
Mem:       3355256    1251112    2104144          0      48664     391972
-/+ buffers/cache:     810476    2544780

系统支持 PAE，请参阅：

administrator@Root2:~$ grep --color=always -i PAE /proc/cpuinfo
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dts
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dts

我们对系统进行了全面修补并尝试运行手动 PAE 升级，请参阅：

administrator@Root2:~$ sudo apt-get install linux-generic-pae linux-headers-generic-pae
[sudo] password for administrator: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
linux-generic-pae is already the newest version.
linux-headers-generic-pae is already the newest version.
The following packages were automatically installed and are no longer required:
  language-pack-zh-hans language-pack-kde-en language-pack-kde-zh-hans
  language-pack-kde-en-base kde-l10n-engb kde-l10n-zhcn
  language-pack-zh-hans-base firefox-locale-zh-hans
  language-pack-kde-zh-hans-base
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

我不确定除了加载 64 位之外还有什么可以尝试识别安装的完整物理内存。有什么想法吗？谢谢！

uname -r 的输出

administrator@Root2:~$ uname -r
3.2.0-24-generic-pae

Answer 1

@fossfreedom - 通过将 BIOS 升级到最新版本，问题已得到解决。谢谢你的提示！查看更改后可用的内存输出：

administrator@Root2:~$ free -m
             total       used       free     shared    buffers     cached
Mem:          4026       1105       2921          0         45        311
-/+ buffers/cache:        748       3278

Answer 2

32 位仅支持 3.2GB 内存。如果您想充分利用内存，您应该升级到 64 位