各位好，我遇到了一个头疼的内存识别问题，想请大家帮忙看看：

我有一台戴尔Precision T7500工作站（当前运行Proxmox系统），为了升级内存，我购入了5根16GB的DDR3 ECC内存。现在BIOS能正常识别所有内存，用dmidecode --type memory查询也能看到每一根内存的详细信息，但系统里free -h输出的总内存却只有31Gi，完全没有达到预期的容量。

以下是相关命令的输出内容：

dmidecode --type memory 输出 #

root@pve:~# dmidecode --type memory

# dmidecode 3.3

Getting SMBIOS data from sysfs.

SMBIOS 2.5 present.

Handle 0x1000, DMI type 16, 15 bytes

Physical Memory Array

Location: System Board Or Motherboard

Use: System Memory

Error Correction Type: Multi-bit ECC

Maximum Capacity: 96 GB

Error Information Handle: Not Provided

Number Of Devices: 6

Handle 0x1100, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 16 GB

Form Factor: DIMM

Set: None

Locator: DIMM 1

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1600 MT/s

Manufacturer: 80CE04B380CE

Serial Number: 391B773A

Asset Tag: 02143621

Part Number: M393B2G70QH0-YK0

Handle 0x1101, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 16 GB

Form Factor: DIMM

Set: None

Locator: DIMM 2

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1600 MT/s

Manufacturer: 80CE04B380CE

Serial Number: 391B7711

Asset Tag: 02143621

Part Number: M393B2G70QH0-YK0

Handle 0x1102, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 16 GB

Form Factor: DIMM

Set: None

Locator: DIMM 3

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1600 MT/s

Manufacturer: 80CE04B380CE

Serial Number: 391B6EDE

Asset Tag: 02143621

Part Number: M393B2G70QH0-YK0

Handle 0x1103, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 16 GB

Form Factor: DIMM

Set: None

Locator: DIMM 4

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1600 MT/s

Manufacturer: 80CE80B380CE

Serial Number: 35B63B0A

Asset Tag: 02130963

Part Number: M393B2G70BH0-YK0

Handle 0x1104, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 16 GB

Form Factor: DIMM

Set: None

Locator: DIMM 5

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1600 MT/s

Manufacturer: 80CE80B380CE

Serial Number: 35D44E74

Asset Tag: 02131163

Part Number: M393B2G70BH0-YK0

Handle 0x1105, DMI type 17, 27 bytes

Memory Device

Array Handle: 0x1000

Error Information Handle: No Error

Total Width: 72 bits

Data Width: 64 bits

Size: 1 GB

Form Factor: DIMM

Set: None

Locator: DIMM 6

Bank Locator: Not Specified

Type: DDR3

Type Detail: Registered (Buffered)

Speed: 1333 MT/s

Manufacturer: 80AD80B380AD

Serial Number: 12171ABD

Asset Tag: 01104661

Part Number: HMT112R7TFR8C-H9

cat /proc/meminfo 输出 #

root@pve:~# cat /proc/meminfo

MemTotal:       32855880 kB

MemFree:         5121012 kB

MemAvailable:    7798196 kB

Buffers:          404944 kB

Cached:          2308224 kB

SwapCached:            0 kB

Active:          3655696 kB

Inactive:        3840888 kB

Active(anon):    2158044 kB

Inactive(anon):  3041444 kB

Active(file):    1497652 kB

Inactive(file):   799444 kB

Unevictable:       47320 kB

Mlocked:           47320 kB

SwapTotal:             0 kB

SwapFree:              0 kB

Dirty:               436 kB

Writeback:             0 kB

AnonPages:       4784652 kB

Mapped:           566780 kB

Shmem:            408372 kB

KReclaimable:     843760 kB

Slab:            5255540 kB

SReclaimable:     843760 kB

SUnreclaim:      4411780 kB

KernelStack:       17104 kB

PageTables:        40440 kB

NFS_Unstable:          0 kB

Bounce:                0 kB

WritebackTmp:          0 kB

CommitLimit:    16427940 kB

Committed_AS:   13810796 kB

VmallocTotal:   34359738367 kB

VmallocUsed:      978100 kB

VmallocChunk:          0 kB

Percpu:           153856 kB

HardwareCorrupted:     0 kB

AnonHugePages:   2025472 kB

ShmemHugePages:        0 kB

ShmemPmdMapped:        0 kB

FileHugePages:         0 kB

FilePmdMapped:         0 kB

HugePages_Total:       0

HugePages_Free:        0

HugePages_Rsvd:        0

HugePages_Surp:        0

Hugepagesize:       2048 kB

Hugetlb:               0 kB

DirectMap4k:    13174756 kB

DirectMap2M:    20377600 kB

DirectMap1G:           0 kB

free -h 输出 #

root@pve:~# free -h

total        used        free      shared  buff/cache   available

Mem:            31Gi        23Gi       4.9Gi       406Mi       3.4Gi       7.4Gi

Swap:             0B          0B          0B

我已经尝试过多种内存配置方案：更换插槽位置、调整内存插放顺序、拔掉那根1GB的旧内存、单独测试不同型号的16GB内存等等，但总内存显示依旧只有31Gi，实在找不到问题所在，希望有经验的朋友能给我一些排查思路或解决办法，谢谢！

备注：内容来源于stack exchange，提问作者Kujonello