Determine maximum memory capacity.

Use a dmidecode utility to decode SMBIOS table contents related to the memory and display using a human-readable format.

$ sudo dmidecode --type memory
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x003E, DMI type 16, 23 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 16 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2

Handle 0x003F, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x003E
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 8192 MB
	Form Factor: DIMM
	Set: None
	Locator: DIMM1
	Bank Locator: Not Specified
	Type: DDR3
	Type Detail: Synchronous
	Speed: 1600 MT/s
	Manufacturer: 1119
	Serial Number: 0010260A10D2
	Asset Tag: 01193300
	Part Number: S939A2UGS-ITR     
	Rank: 2
	Configured Memory Speed: 1600 MT/s

Handle 0x0041, DMI type 17, 34 bytes
Memory Device
	Array Handle: 0x003E
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 8192 MB
	Form Factor: DIMM
	Set: None
	Locator: DIMM2
	Bank Locator: Not Specified
	Type: DDR3
	Type Detail: Synchronous
	Speed: 1600 MT/s
	Manufacturer: 1119
	Serial Number: 0010260A10F2
	Asset Tag: 01193300
	Part Number: S939A2UGS-ITR     
	Rank: 2
	Configured Memory Speed: 1600 MT/s

Narrow down the results.

$ sudo dmidecode --type 16    
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x003E, DMI type 16, 23 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 16 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2

Get only the maximum memory capacity.

$ sudo dmidecode --type memory | awk '/^\tMaximum Capacity/ {print $(NF-1) " " $NF}'
16 GB
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