我有 4*4Gb 内存条中的 8Gb。我安装了一些新的内存条，将主机升级到4*8Gb。然而，我仍然只有 16GB 可用空间（安装的物理空间为 32GB）。无论设置是什么，Linux 似乎只能看到已安装的 ram 的一半。
硬件没有问题（内存已在另外两台机器上测试过）
BIOS = 32Gb 检测到 Linux 只看到 16GB 内存 dmidecode 看到我所有的 4 根内存条
# dmidecode -t 17
# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.
Handle 0x000E, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x000D
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: SODIMM
Set: None
Locator: DIMM0
Bank Locator: BANK 0
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Unknown
Serial Number: E09028A6
Asset Tag: Unknown
Part Number: CT102464BF160B.C16
Rank: 2
Configured Clock Speed: 1600 MT/s
Handle 0x000F, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x000D
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: SODIMM
Set: None
Locator: DIMM1
Bank Locator: BANK 1
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Unknown
Serial Number: E0902887
Asset Tag: Unknown
Part Number: CT102464BF160B.C16
Rank: 2
Configured Clock Speed: 1600 MT/s
Handle 0x0010, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x000D
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: SODIMM
Set: None
Locator: DIMM1
Bank Locator: BANK 2
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Unknown
Serial Number: E09027D2
Asset Tag: Unknown
Part Number: CT102464BF160B.C16
Rank: 2
Configured Clock Speed: 1600 MT/s
Handle 0x0011, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x000D
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 8192 MB
Form Factor: SODIMM
Set: None
Locator: DIMM3
Bank Locator: BANK 3
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Unknown
Serial Number: E0902882
Asset Tag: Unknown
Part Number: CT102464BF160B.C16
Rank: 2
Configured Clock Speed: 1600 MT/s
知道为什么，以及有关如何激活所有这些的建议吗？ （目前运行 Fedora26/64 位，也在 Debian/64 位上进行了测试）
内存信息：
bash-4.4$ cat /proc/meminfo
MemTotal: 16307964 kB
MemFree: 2589188 kB
MemAvailable: 9856496 kB
Buffers: 428964 kB
Cached: 4553096 kB
SwapCached: 132 kB
Active: 7578520 kB
Inactive: 4187932 kB
Active(anon): 3926432 kB
Inactive(anon): 745528 kB
Active(file): 3652088 kB
Inactive(file): 3442404 kB
Unevictable: 24328 kB
Mlocked: 24328 kB
SwapTotal: 15569916 kB
SwapFree: 15528188 kB
Dirty: 3060 kB
Writeback: 0 kB
AnonPages: 6806540 kB
Mapped: 1573064 kB
Shmem: 363464 kB
Slab: 645716 kB
SReclaimable: 513068 kB
SUnreclaim: 132648 kB
KernelStack: 11552 kB
PageTables: 55452 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 23723896 kB
Committed_AS: 12692532 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 0 kB
VmallocChunk: 0 kB
HardwareCorrupted: 0 kB
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 832256 kB
DirectMap2M: 15822848 kB
DirectMap1G: 1048576 kB
free -m结果与一致，/proc/meminfo
但dmidecode仍然确认有 4 个不同的 8Gb 内存条
total used free shared buff/cache available
Mem: 15920 4074 5169 204 6675 12038
BIOS 非常有限，我只能管理启动顺序。没有关于内存或其他任何东西的选项。在 BIOS 方面，确认存在 32Gb
机器型号：Aspire V3-772G 最后加载的BIOS：V1.15
这就是我能给出的所有有用的信息，dmesg分析不允许得到任何有用的东西。
只有关于 kvm/virsh 设置的循环警告：像这样的循环中的块，根本没有其他信息
[12341.196455] set_target_expiration: 30 callbacks suppressed
[12341.196459] kvm: vcpu 0: requested 100012 ns lapic timer period limited to 500000 ns
[12341.306246] kvm: vcpu 0: requested 292092 ns lapic timer period limited to 500000 ns
[12341.704421] kvm: vcpu 0: requested 473064 ns lapic timer period limited to 500000 ns
[12341.914420] kvm: vcpu 0: requested 468345 ns lapic timer period limited to 500000 ns
[12341.924470] kvm: vcpu 0: requested 405938 ns lapic timer period limited to 500000 ns
[12341.996356] kvm: vcpu 0: requested 100012 ns lapic timer period limited to 500000 ns
[12342.096905] kvm: vcpu 0: requested 106350 ns lapic timer period limited to 500000 ns
[12342.135880] kvm: vcpu 0: requested 424319 ns lapic timer period limited to 500000 ns
[12342.406376] kvm: vcpu 0: requested 113630 ns lapic timer period limited to 500000 ns
[12342.474998] kvm: vcpu 0: requested 271348 ns lapic timer period limited to 500000 ns
我的发行版和内核：
[root@h2g2w ~]# cat /etc/*release*
Fedora release 26 (Twenty Six)
NAME=Fedora
VERSION="26 (Server Edition)"
ID=fedora
VERSION_ID=26
PRETTY_NAME="Fedora 26 (Server Edition)"
ANSI_COLOR="0;34"
CPE_NAME="cpe:/o:fedoraproject:fedora:26"
HOME_URL="https://fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=26
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=26
PRIVACY_POLICY_URL=https://fedoraproject.org/wiki/Legal:PrivacyPolicy
VARIANT="Server Edition"
VARIANT_ID=server
Fedora release 26 (Twenty Six)
ROS fuerte (Fuerte Turtle)
Fedora release 26 (Twenty Six)
cpe:/o:fedoraproject:fedora:26
[root@h2g2w ~]# uname -a
Linux h2g2w.local 4.14.11-200.fc26.x86_64 #1 SMP Wed Jan 3 13:58:53 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@h2g2w ~]#
但这是没用的，正如我在评论交流中所说的，我尝试过其他发行版，甚至 BSD
构造函数规格：
Overview
Specifications
Acer Aspire V3-772G-9829 - 17.3" - Core i7 4702MQ - 8 GB RAM - 1 TB HDD
Part Number: NX.M74AA.002
General
Packaged Quantity
1
Notebook type
Gaming, HD display, Desktop replacement
Manufacturer
Acer
Processor / Chipset
CPU
Intel Core i7 (4th Gen) 4702MQ / 2.2 GHz
Max Turbo Speed
3.2 GHz
Number of Cores
Quad-Core
Cache
L3 - 6 MB
64-bit Computing
Yes
Chipset Type
Mobile Intel HM86 Express
Features
Hyper-Threading Technology, Intel Smart Cache, Intel Turbo Boost Technology 2.0
Cache Memory
Type
L3 cache
Installed Size
6 MB
Memory
Max Supported Size
32 GB
Technology
DDR3L SDRAM
Speed
1600 MHz / PC3-12800 - 1600 MHz
Form Factor
SO-DIMM 204-pin
Slots Qty
4
Storage
Interface
Serial ATA-300
Optical Drive
DVD±RW (±R DL) / DVD-RAM fixed
那么为什么 Linux（或任何其他操作系统，如 BSD 等）仅检测/激活 16GB？如何使用完整的内存？
答案1
好吧，终于我发现发生了什么......这并不是真正的硬件问题，而是翻新机降级到主板版本，仅限支持16GB......在32GB型号的“机箱”内......但它已经能够检测到所有的内存条...但只激活 2 个插槽。
所以我会等到下次有机会便宜买一台 32/64Gb 的机器。