我刚刚安装了 Ubuntu Server 11.10 64 位，当我执行 free -m 时，它只显示总共 24094。
这是一个相当新的版本，我能够在 Solaris 11 上看到全部 32GB。
total used free shared buffers cached
Mem: 24094 582 23511 0 11 195
-/+ buffers/cache: 375 23718
Swap: 24571 0 24571
我正在运行带有 AMD 8150 Black Edition 处理器的 Gigabyte 990FXA-UD5 主板。
任何意见都值得赞赏。
** 更新 **
dmidecode 显示第一个插槽中的 DIMM 仅为 4096 MB
Handle 0x002A, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0029
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: A0
Bank Locator: Bank0/1
Type: Unknown
Type Detail: None
Speed: 1333 MHz (0.8 ns)
Manufacturer:
Serial Number:
Asset Tag:
Part Number:
Handle 0x002B, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0029
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: A1
Bank Locator: Bank2/3
Type: Unknown
Type Detail: None
Speed: 1333 MHz (0.8 ns)
Manufacturer:
Serial Number:
Asset Tag:
Part Number:
Handle 0x002C, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0029
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: A2
Bank Locator: Bank4/5
Type: Unknown
Type Detail: None
Speed: 1333 MHz (0.8 ns)
Manufacturer:
Serial Number:
Asset Tag:
Part Number:
Handle 0x002D, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0029
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: DIMM
Set: None
Locator: A3
Bank Locator: Bank6/7
Type: Unknown
Type Detail: None
Speed: 1333 MHz (0.8 ns)
Manufacturer:
Serial Number:
Asset Tag:
Part Number:
答案1
输出是什么：
sudo lshw -C memory
我也遇到过类似的问题，Ubuntu 无法检测到我的 RAM，但后来发现是物理上松动了。这很奇怪，我知道。
尝试在 DIMM 之间切换 RAM，是 RAM 还是 DIMM？还是 Ubuntu？你永远不知道！