3

I have bought new RAM, and it's not detected.

In short

I got new RAM, 16 GB, to switch my old one, 4 GB + 4 GB. New one isn't detected by my laptop OS(?)/software(?). But when I installed it, it didn't work, I got only 4 GB.

Long one

I got new RAM, 16 GB, to switch my old one, 4 GB + 4 GB, so it will be 20 GB. But when I installed it, it didn't work, what I mean is I opened System Monitor and it showed (and shows) only 4 GB. System Monitor

But the things is, some programs/utils cat detect it here I will paste all the output of the commands I've tried

inxi -Fxz

System:    Host: lmde Kernel: 4.8.0-53-generic x86_64 (64 bit gcc: 5.4.0)
           Desktop: Cinnamon 3.4.3 (Gtk 3.18.9-1ubuntu3.3) Distro: Linux Mint 18.2 Sonya
Machine:   System: LENOVO product: 20250 v: Lenovo Z710
           Mobo: LENOVO model: Durian 7A1 v: 31900004Std Bios: LENOVO v: 7FCN35WW date: 09/02/2013
CPU:       Quad core Intel Core i7-4700MQ (-HT-MCP-) cache: 6144 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 19156
           clock speeds: max: 2400 MHz 1: 2400 MHz 2: 2147 MHz 3: 2350 MHz 4: 2400 MHz 5: 2400 MHz 6: 2400 MHz
           7: 2399 MHz 8: 2400 MHz
Graphics:  Card-1: Intel 4th Gen Core Processor Integrated Graphics Controller bus-ID: 00:02.0
           Card-2: NVIDIA GK107M [GeForce GT 745M] bus-ID: 01:00.0
           Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa) FAILED: nouveau
           Resolution: 1920x1080@60.02hz
           GLX Renderer: Mesa DRI Intel Haswell Mobile GLX Version: 3.0 Mesa 12.0.6 Direct Rendering: Yes
Audio:     Card-1 Intel 8 Series/C220 Series High Definition Audio Controller
           driver: snd_hda_intel bus-ID: 00:1b.0
           Card-2 Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller
           driver: snd_hda_intel bus-ID: 00:03.0
           Sound: Advanced Linux Sound Architecture v: k4.8.0-53-generic
Network:   Card-1: Intel Wireless 7260 driver: iwlwifi bus-ID: 07:00.0
           IF: wlp7s0 state: up mac: <filter>
           Card-2: Qualcomm Atheros QCA8171 Gigabit Ethernet driver: alx port: 3000 bus-ID: 08:00.0
           IF: enp8s0 state: down mac: <filter>
Drives:    HDD Total Size: 1240.3GB (6.3% used) ID-1: /dev/sda model: ST1000LM014 size: 1000.2GB
           ID-2: /dev/sdd model: ADATA_SP580 size: 240.1GB
Partition: ID-1: / size: 220G used: 20G (10%) fs: ext4 dev: /dev/sdd2
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 59.0C mobo: 59.0C gpu: 45.0
           Fan Speeds (in rpm): cpu: N/A
Info:      Processes: 294 Uptime: 1:24 Memory: 2301.1/3863.2MB Init: systemd runlevel: 5 Gcc sys: 5.4.0
           Client: Shell (zsh 5.1.1) inxi: 2.2.35

sudo lshw -short -C memory (pasting with sudo so others cat just copy-paste)

H/W path               Device     Class          Description
============================================================
/0/0                              memory         128KiB BIOS
/0/4/b                            memory         32KiB L1 cache
/0/4/c                            memory         256KiB L2 cache
/0/4/d                            memory         6MiB L3 cache
/0/a                              memory         32KiB L1 cache
/0/2a                             memory         20GiB System Memory
/0/2a/0                           memory         16GiB SODIMM DDR3 Synchronous 1600 MHz (0,6 ns)
/0/2a/1                           memory         DIMM [empty]
/0/2a/2                           memory         4GiB SODIMM DDR3 Synchronous 1600 MHz (0,6 ns)
/0/2a/3                           memory         DIMM [empty]

sudo lshw -class memory

  *-firmware
       description: BIOS
       vendor: LENOVO
       physical id: 0
       version: 7FCN35WW
       date: 09/02/2013
       size: 128KiB
       capacity: 4032KiB
       capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification uefi
  *-cache:0
       description: L1 cache
       physical id: b
       slot: L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: synchronous internal write-back instruction
  *-cache:0
       description: L1 cache
       physical id: b
       slot: L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: synchronous internal write-back instruction
       configuration: level=1
  *-cache:1
       description: L2 cache
       physical id: c
       slot: L2 Cache
       size: 256KiB
       capacity: 256KiB
       capabilities: synchronous internal write-back unified
       configuration: level=2
  *-cache:2
       description: L3 cache
       physical id: d
       slot: L3 Cache
       size: 6MiB
       capacity: 6MiB
       capabilities: synchronous internal write-back unified
       configuration: level=3
  *-cache
       description: L1 cache
       physical id: a
       slot: L1 Cache
       size: 32KiB
       capacity: 32KiB
       capabilities: synchronous internal write-back data
       configuration: level=1
  *-memory
       description: System Memory
       physical id: 2a
       slot: System board or motherboard
       size: 20GiB
     *-bank:0
          description: SODIMM DDR3 Synchronous 1600 MHz (0,6 ns)
          product: CT204864BF160B.C16
          vendor: Unknown
          physical id: 0
          serial: A4205EAD
          slot: DIMM0
          size: 16GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     *-bank:1
          description: DIMM [empty]
          product: Empty
          vendor: Empty
          physical id: 1
          serial: Empty
          slot: DIMM1
     *-bank:2
          description: SODIMM DDR3 Synchronous 1600 MHz (0,6 ns)
          product: M471B5173BH0-YK0
          vendor: Samsung
          physical id: 2
          serial: 136B8093
          slot: DIMM2
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     *-bank:3
          description: DIMM [empty]
          product: Empty
          vendor: Empty
          physical id: 3
          serial: Empty
          slot: DIMM3

sudo dmidecode

free -m

              total        used        free      shared  buff/cache   available
Mem:           3863        2406         277         430        1178         696
Swap:             0           0           0

cat /proc/cmdline

BOOT_IMAGE=/boot/vmlinuz-4.8.0-53-generic root=UUID=91af3ab8-8c93-40ef-930a-2dc7038f2dfc ro elevator=deadline quiet splash vt.handoff=7

dmesg | grep -i memory did but it's very long

Also: -I booted to BIOS and it showed that there is 20 GB (but it said in MB, something like 20480 MB) -I visited Intel page for my processor(google for Intel® Core™ i7-4700MQ Processor can't paste links, have newbie restrictions) for my CPU and it said that it does support 32 GB -I booted to Windows 10 live CD and it show that it has 20 GB but only 4 GB is available -I did memtest86 here are the screenshot with results memtest86 what I don't like about it is that in the top left corner it shows that [c]Memory: 4009 MB[/c]. So was the 16 GB detected? -I booted to Linux Mint live CD and it showed exactly the same as current version (4 GB). -I found on internet that it can be caused by that contacts on the module was made "dirty" with dirt on my hands, so plugged it out got, wipe with ethanol, I did that but not with ethanol, instead of it I used vodka same results didn't work. -I swapped RAM modules, didn't work. I don't remember exactly, but also with installation the GRUB menu broke, what I mean is I got black screen for 3 seconds (which I can configure from /etc/default/grub).

The only thing where I kind of "broke the rule" is before buying it, I visited (google for Lenovo Lenovo Z710 compatible upgrades crucial) crucial website for my laptop (they have very fluent interface to choose the upgrades) and it says that the max RAM is 16 GB (8 + 8 ), I've ignored it.


[update]

Antz answer kind of solves my problem, but the real answer with code example was given on official Linux Mint Forum. sudo dmidecode gave huge output, but there it said about error that I had

Handle 0x0005, DMI type 5, 24 bytes
Memory Controller Information
   Error Detecting Method: None
   Error Correcting Capabilities:
      None
   Supported Interleave: One-way Interleave
   Current Interleave: One-way Interleave
   Maximum Memory Module Size: 8192 MB
  • 1
    I'm afraid the answer is in your question: max memory is 8 GB per slot. Your new RAM module, is clearly identified as a 16 GB one and is then ignored. – xhienne Sep 3 '17 at 0:28
  • if the hardware says you only have 4Gb then Linux doesn't stand much of a chance – Jeff Schaller Sep 3 '17 at 1:18
4

In summary, one of two things generally happens. The memory works, but is limited to the maximum amount supported by the motherboard, or the memory doesn't work at all.

Let me be a bit detail to you.

On every motherboard, there is a controller for accessing the RAM. The limiting factor is how much memory can be accessed (or addressed) by that memory controller. Theoretically, a 64-bit CPU can access 2^64 bytes of RAM. For practical reasons, however, the number of addresses lines actually etched into a motherboard is much smaller, and the controller is created to be able to access up to a specific number of addresses. It can address fewer memory locations just fine as well. That determines the range and maximum amount of memory.

So when memory is installed with more addressable bytes than the controller understands, the best outcome is that only the lower portion of the RAM is used. However, because of the way memory is constructed, it's also possible that the larger memory won't work at all as that's the case with yours.

But again, it depends on the motherboard on how it handles memory errors.

This stackexchange site gives more detailed information concerning your RAM issue. What happens when more RAM is installed than the motherboard supports?

You can also read this: RAM.

  • 1
    “Theoretically, a 64-bit CPU can access 2^64 bytes of RAM.” This is not true. The amount of memory that a CPU can address has very little relation with the N in “N-bit CPU”. It can be higher (e.g. x86_32 with PAE can access >4GB RAM) or lower (e.g. any current x86_64 CPU can't access more than 64TB RAM). – Gilles 'SO- stop being evil' Sep 4 '17 at 20:48

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