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Linux / Unix: Find Out Maximum RAM Supported By The Server BIOS / Motherboard

How do I find out the maximum RAM supported by the Dell / HP / IBM / Oracle / Sun / Intel / AMD server under Linux / Unix / HP-UX / FreeBSD / Solaris operating systems without rebooting the server or opening server case (cabinet)?

Most modern server supports 16GB, 32GB, 64GB or more RAM and has 4 or more DIMM slots. To find out what is the maximum system can support type the following command as root user:
# dmidecode -t 16
Sample outputs:

# dmidecode 2.11
SMBIOS 2.5 present.
Handle 0x0016, DMI type 16, 15 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 64 GB
	Error Information Handle: Not Provided
	Number Of Devices: 8

 

(Fig.01: This server supports maximum 64 GB and has 8 DIMM slots)

However, my old good home server can support max 4GB ram:
# dmidecode -t 16
Sample outputs:

 

# dmidecode 2.9
SMBIOS 2.6 present.
Handle 0x0008, DMI type 16, 15 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 4 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2

 

(Fig.02: My home server supports maximum 4 GB RAM and has total 2 DIMM slots)

You can find out currently installed memory information (DIMM and its slots) by typing the following command:
# dmidecode -t 17
Sample outputs:

 

# dmidecode 2.9
SMBIOS 2.6 present.
Handle 0x000A, DMI type 17, 28 bytes
Memory Device
	Array Handle: 0x0008
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 2048 MB
	Form Factor: DIMM
	Set: None
	Locator: DIMM0
	Bank Locator: BANK0
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz (1.5 ns)
	Manufacturer: Manufacturer00
	Serial Number: SerNum00
	Asset Tag: AssetTagNum0
	Part Number: ModulePartNumber00
Handle 0x000C, DMI type 17, 28 bytes
Memory Device
	Array Handle: 0x0008
	Error Information Handle: Not Provided
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: DIMM
	Set: None
	Locator: DIMM1
	Bank Locator: BANK1
	Type: Unknown
	Type Detail: Unknown
	Speed: Unknown
	Manufacturer: Manufacturer01
	Serial Number: SerNum01
	Asset Tag: AssetTagNum1
	Part Number: ModulePartNumber01

 

(Fig.03: Find out installed RAM information)

Another output from one of my personal server:
# dmidecode -t 17
Sample outputs:

 

# dmidecode 2.11
SMBIOS 2.5 present.
Handle 0x0013, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: No Error
	Total Width: 40968 bits
	Data Width: 41032 bits
	Size: 512 MB
	Form Factor: DIMM
	Set: 1
	Locator: J6G1
	Bank Locator: DIMM 0
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Kingston
	Serial Number: 80CC2564
	Asset Tag: 00000903
	Part Number: 393930353332302D3030322E4130314C4600
Handle 0x0014, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: No Error
	Total Width: 41480 bits
	Data Width: 41544 bits
	Size: 512 MB
	Form Factor: DIMM
	Set: 1
	Locator: J6G2
	Bank Locator: DIMM 1
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Kingston
	Serial Number: 80CC1E64
	Asset Tag: 00000903
	Part Number: 393930353332302D3030322E4130314C4600
Handle 0x0015, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: No Error
	Total Width: 41992 bits
	Data Width: 42056 bits
	Size: 512 MB
	Form Factor: DIMM
	Set: 1
	Locator: J6H1
	Bank Locator: DIMM 2
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Kingston
	Serial Number: BCCCFD8D
	Asset Tag: 00000833
	Part Number: 393930353332302D3030322E4130314C4600
Handle 0x0016, DMI type 17, 27 bytes
Memory Device
	Array Handle: 0x0012
	Error Information Handle: No Error
	Total Width: 42504 bits
	Data Width: 42568 bits
	Size: 512 MB
	Form Factor: DIMM
	Set: 1
	Locator: J6H2
	Bank Locator: DIMM 3
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz
	Manufacturer: Kingston
	Serial Number: BCCCDF8D
	Asset Tag: 00000833
	Part Number: 393930353332302D3030322E4130314C4600

 

(Fig.04: This server has 512MBx4 Kingston DIMM installed)
 

memconf Perl Script

You can download memconf here and run it as follows:

 
$ cd /tmp
$ wget http://www.4schmidts.com/unix/memconf.gz
$ gunzip memconf.gz
# perl memconf -v

Sample outputs:

memconf:  V2.22 30-Jan-2012 http://www.4schmidts.com/unix.html
hostname: dbmsyq05.nixcraft.net.in
Supermicro X7DBR-3 (Dual-Core Intel(R) Xeon(TM) 2000MHz)
Memory Error Correction: None
Maximum Memory: 65536MB (64GB)
DIMM1A Bank1: 2048MB 667MHz Synchronous DDR2 DIMM, 0000
DIMM2A Bank2: 2048MB 667MHz Synchronous DDR2 DIMM, 0000
DIMM3A Bank3: 2048MB 667MHz Synchronous DDR2 DIMM, 0000
DIMM4A Bank4: 2048MB 667MHz Synchronous DDR2 DIMM, 0000
empty memory sockets: DIMM1B Bank1, DIMM2B Bank2, DIMM3B Bank3, DIMM4B Bank4
total memory = 8192MB (8GB)
WARNING: ECC memory detected, but ECC is not enabled in the BIOS.

 

(Fig.05: Runs on Linux / Solaris / HP-UX / FreeBSD to displays memory modules installed in server)
 

Online Info

Another option is to visit your server or computer manufacturer website and find out the same info.

Originally posted 2016-03-09 02:43:16.

About admin

I have been working with Linux based systems since 2002. I hope the article published on this site will be useful to those new to server administration.