Arch Linux

addictedtoflames

Member

Registered: 2014-06-13

Posts: 6

System not detecting full amount of installed RAM

Heya, I'm running Arch on a Samsung np535u3c laptop with 6GB of memory installed (4GB soldered to motherboard and 1 2GB SODIMM) and it would seem the 2GB stick is not being marked as available for the system to use (I have tried using a different stick so I'm pretty sure it's not a hardware issue unless it's something wrong with the socket). When I run 'free -h' I get

$free -h
              total        used        free      shared  buff/cache   available
Mem:           3.6G        1.5G        1.7G         11M        447M        1.9G
Swap:          3.0G          0B        3.0G

dmesg also shows the same ammount:

$dmesg | grep -i memory
[    0.000000] Scanning 1 areas for low memory corruption
[    0.000000] Base memory trampoline at [ffff880000099000] 99000 size 24576
[    0.000000] Early memory node ranges
[    0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.000000] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff]
[    0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000dffff]
[    0.000000] PM: Registered nosave memory: [mem 0x000e0000-0x000fffff]
[    0.000000] PM: Registered nosave memory: [mem 0xae740000-0xae8d2fff]
[    0.000000] PM: Registered nosave memory: [mem 0xae8d3000-0xae8dffff]
[    0.000000] PM: Registered nosave memory: [mem 0xae8e0000-0xaec31fff]
[    0.000000] PM: Registered nosave memory: [mem 0xaec32000-0xaefd6fff]
[    0.000000] PM: Registered nosave memory: [mem 0xaefd8000-0xaf1dafff]
[    0.000000] PM: Registered nosave memory: [mem 0xaf5e3000-0xaf7f3fff]
[    0.000000] PM: Registered nosave memory: [mem 0xaf800000-0xfebfffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfec00000-0xfec00fff]
[    0.000000] PM: Registered nosave memory: [mem 0xfec01000-0xfec0ffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfec10000-0xfec10fff]
[    0.000000] PM: Registered nosave memory: [mem 0xfec11000-0xfecfffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed00000-0xfed00fff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed01000-0xfed3ffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed40000-0xfed44fff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed45000-0xfed7ffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed80000-0xfed8ffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfed90000-0xfeffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xff000000-0xffffffff]
[    0.000000] PM: Registered nosave memory: [mem 0x100000000-0x100000fff]
[    0.000000] Memory: 3748800K/3894216K available (5832K kernel code, 970K rwdata, 1856K rodata, 1200K init, 1156K bss, 145416K reserved, 0K cma-reserved)
[    0.012021] Freeing SMP alternatives memory: 24K (ffffffff81a20000 - ffffffff81a26000)
[    0.640880] Freeing initrd memory: 5460K (ffff880037546000 - ffff880037a9b000)
[    0.641148] Scanning for low memory corruption every 60 seconds
[    0.683735] Freeing unused kernel memory: 1200K (ffffffff818f4000 - ffffffff81a20000)
[    0.684134] Freeing unused kernel memory: 300K (ffff8800015b5000 - ffff880001600000)
[    0.684975] Freeing unused kernel memory: 192K (ffff8800017d0000 - ffff880001800000)
[    3.503601] Found memory entry in CRAT table with proximity_domain=0
[    3.503604] Found memory entry in CRAT table with proximity_domain=0
[    3.503606] Found memory entry in CRAT table with proximity_domain=0
[    3.519970] [TTM] Zone  kernel: Available graphics memory: 1877988 kiB
[    3.520025] [drm] radeon: 256M of VRAM memory ready
[    3.520027] [drm] radeon: 1024M of GTT memory ready.
[    4.007206] Non-volatile memory driver v1.3

However, all of the memory is detected by the BIOS and 'dmidecode --type memory' gives

#dmidecode --type memory
# dmidecode 3.0
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x0012, DMI type 16, 23 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 8 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2

Handle 0x0014, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 4096 MB
	Form Factor: DIMM
	Set: None
	Locator: A1_DIMM0
	Bank Locator: A1_BANK0
	Type: DDR3
	Type Detail: Synchronous Unbuffered (Unregistered)
	Speed: 667 MHz
	Manufacturer: A1_Manufacturer0
	Serial Number: A1_SerNum0
	Asset Tag: A1_AssetTagNum0
	Part Number: Array1_PartNumber0
	Rank: Unknown
	Configured Clock Speed: Unknown

Handle 0x0016, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 2048 MB
	Form Factor: DIMM
	Set: None
	Locator: A1_DIMM1
	Bank Locator: A1_BANK1
	Type: DDR3
	Type Detail: Synchronous Unbuffered (Unregistered)
	Speed: 667 MHz
	Manufacturer: Samsung         
	Serial Number: 949D8C09  
	Asset Tag: A1_AssetTagNum1
	Part Number: M471B5673GB0-CH9  
	Rank: 2
	Configured Clock Speed: 54205 MHz

so I know the system can detect all of the memory. lshw also shows both sticks.

I have run memtest86 and it reports no errors and I am definitely running the 64 bit version of the OS

$uname -a
Linux Camus 4.5.1-1-ARCH #1 SMP PREEMPT Sat Apr 23 19:05:03 BST 2016 x86_64 GNU/Linux

When I was running windows it would show about 5.5GB as available as I would expect however once I installed Arch Windows started showing the same 3.6GB (Windows is no-longer installed on the machine so I can't check whether this is still the case)

Has anybody run into anything similar before? Any advice would be greatly appreciated.