Mostly, you will find maximum supported RAM by your system from the BIOS, Product catalog, or manuals. Here is the simple, yet useful trick, to find out maximum supported RAM using Dmidecode without opening the system chassis or referring the BIOS, product catalogs.
What is Dmidecode?
As you may know, Dmidecode is a tool for dumping a computer’s DMI (some say SMBIOS) table contents in a human-readable format. This table contains a description of the system’s hardware components, as well as other useful pieces of information such as serial numbers and BIOS revision. Using Dmidecode, you can retrieve this information without having to probe for the actual hardware.
Find out the maximum RAM supported by your system
Make sure you have installed dmidecode on your system. I think it will be automatically installed while installing your OS, but I am not sure though.
On Deb based system:
sudo apt-get install dmidecode
On RPM based system:
sudo yum install dmidecode
On SUSE/openSUSE:
sudo zypper in dmidecode
Well, we installed dmidecode. Let us find out the maximum RAM supported. To do that, enter the following command:
sudo dmidecode -t 16
Sample output:
# dmidecode 2.12 SMBIOS 2.6 present. Handle 0x0014, DMI type 16, 15 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
As you see in the above output, my system will support RAM upto 16GB, and it has two RAM slots. Pretty easy, isn’t it?
Well, let us find out the currently installed RAM details.
sudo dmidecode -t 17
Sample output:
# dmidecode 2.12 SMBIOS 2.6 present. Handle 0x0017, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: Unknown    Data Width: Unknown    Size: No Module Installed    Form Factor: DIMM    Set: None    Locator: DIMM_B    Bank Locator: BANK 2    Type: Unknown    Type Detail: None    Speed: Unknown    Manufacturer: Not Specified    Serial Number: Not Specified    Asset Tag: Not Specified    Part Number: Not Specified    Rank: Unknown Handle 0x0015, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: 64 bits    Data Width: 64 bits    Size: 4096 MB    Form Factor: SODIMM    Set: None    Locator: DIMM_A    Bank Locator: BANK 0    Type: DDR3    Type Detail: Synchronous    Speed: 1067 MHz    Manufacturer: 014F    Serial Number: 00092AF2    Asset Tag: 54114000       Part Number: JM1066KSN-4G        Rank: Unknown
As per the above output, I have installed one RAM in DIMM slot 1. The RAM size is 4GB, and it’s type and speed is DDR3 and 1067 MHz respectively.
Also, we can have the complete RAM details using the following commands.
sudo dmidecode -t memory sudo dmidecode -t memory | less sudo dmidecode -t memory | more
Sample output:
# dmidecode 2.12 SMBIOS 2.6 present. Handle 0x0014, DMI type 16, 15 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 0x0017, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: Unknown    Data Width: Unknown    Size: No Module Installed    Form Factor: DIMM    Set: None    Locator: DIMM_B    Bank Locator: BANK 2    Type: Unknown    Type Detail: None    Speed: Unknown    Manufacturer: Not Specified    Serial Number: Not Specified    Asset Tag: Not Specified    Part Number: Not Specified    Rank: Unknown Handle 0x0015, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: 64 bits    Data Width: 64 bits    Size: 4096 MB    Form Factor: SODIMM    Set: None    Locator: DIMM_A    Bank Locator: BANK 0    Type: DDR3    Type Detail: Synchronous    Speed: 1067 MHz    Manufacturer: 014F    Serial Number: 00092AF2    Asset Tag: 54114000       Part Number: JM1066KSN-4G        Rank: Unknown
Curious to know the complete system details such as Motherboard, Memory, Bios etc? Well, enter the following command to get all details.
sudo dmidecode
Sample output:
# dmidecode 2.12 SMBIOS 2.6 present. 48 structures occupying 2173 bytes. Table at 0x000EB840. Handle 0xDA00, DMI type 218, 251 bytes OEM-specific Type    Header and Data:       DA FB 00 DA B2 00 0D 5F 0F 37 40 7D 00 00 00 00       00 7E 00 01 00 00 00 DC 01 00 80 02 00 DD 01 00       80 03 00 75 01 01 80 01 00 76 01 02 80 01 00 2D       01 03 80 01 00 2E 01 03 80 00 00 81 01 07 80 00       00 82 01 07 80 01 00 83 01 08 80 00 00 84 01 08       80 01 00 85 01 06 80 00 00 86 01 06 80 01 00 58       02 05 80 00 00 57 02 05 80 01 00 9C 00 02 00 01       00 9B 00 02 00 00 00 8A 01 03 00 01 00 89 01 03       00 00 00 7F 01 04 00 00 00 80 01 04 00 01 00 53       01 05 00 00 00 52 01 05 00 01 00 7B 01 06 00 00       00 7C 01 06 00 01 00 94 01 07 00 00 00 93 01 07       00 01 00 7D 00 08 00 00 00 2D 00 09 00 01 00 2E       00 09 00 00 00 6E 00 0A 00 00 00 95 00 0B 00 01       00 96 00 0B 00 00 00 2F 02 0C 00 01 00 30 02 0C       00 00 00 50 02 0D 00 00 00 51 02 0D 00 01 00 52       02 0D 00 02 00 FF FF 00 00 00 00 Handle 0xDA01, DMI type 218, 59 bytes OEM-specific Type    Header and Data:       DA 3B 01 DA B2 00 0D 5F 0F 37 40 53 02 0D 00 03       00 54 02 0D 00 04 00 56 02 0D 00 05 00 4B 01 0E       00 01 00 4A 01 0E 00 00 00 EA 00 0F 00 01 00 EB       00 0F 00 00 00 FF FF 00 00 00 00 Handle 0x0004, DMI type 4, 42 bytes Processor Information    Socket Designation: CPU 1    Type: Central Processor    Family: Core i3    Manufacturer: Intel              ID: A7 06 03 01 FF FB AB BE    Signature: Type 0, Family 6, Model 42, Stepping 7    Flags:       FPU (Floating-point unit on-chip)       VME (Virtual mode extension)       DE (Debugging extension)       PSE (Page size extension)       TSC (Time stamp counter)       MSR (Model specific registers)       PAE (Physical address extension)       MCE (Machine check exception)       CX8 (CMPXCHG8 instruction supported)       APIC (On-chip APIC hardware supported)       SEP (Fast system call)       MTRR (Memory type range registers)       PGE (Page global enable)       MCA (Machine check architecture)       CMOV (Conditional move instruction supported)       PAT (Page attribute table)       PSE-36 (36-bit page size extension)       CLFSH (CLFLUSH instruction supported)       DS (Debug store)       ACPI (ACPI supported)       MMX (MMX technology supported)       FXSR (FXSAVE and FXSTOR instructions supported)       SSE (Streaming SIMD extensions)       SSE2 (Streaming SIMD extensions 2)       SS (Self-snoop)       HTT (Multi-threading)       TM (Thermal monitor supported)       PBE (Pending break enabled)    Version: Intel(R) Core(TM) i3-2350M CPU @ 2.30GHz         Voltage: 1.1 V    External Clock: 100 MHz    Max Speed: 2300 MHz    Current Speed: 2300 MHz    Status: Populated, Enabled    Upgrade: Other    L1 Cache Handle: 0x0005    L2 Cache Handle: 0x0006    L3 Cache Handle: 0x0007    Serial Number: To Be Filled By O.E.M.    Asset Tag: To Be Filled By O.E.M.    Part Number: To Be Filled By O.E.M.    Core Count: 2    Core Enabled: 1    Thread Count: 2    Characteristics:       64-bit capable Handle 0x0005, DMI type 7, 19 bytes Cache Information    Socket Designation: L1-Cache    Configuration: Enabled, Not Socketed, Level 1    Operational Mode: Write Back    Location: Internal    Installed Size: 64 kB    Maximum Size: 64 kB    Supported SRAM Types:       Other    Installed SRAM Type: Other    Speed: Unknown    Error Correction Type: None    System Type: Unified    Associativity: 8-way Set-associative Handle 0x0006, DMI type 7, 19 bytes Cache Information    Socket Designation: L2-Cache    Configuration: Enabled, Not Socketed, Level 2    Operational Mode: Varies With Memory Address    Location: Internal    Installed Size: 512 kB    Maximum Size: 512 kB    Supported SRAM Types:       Other    Installed SRAM Type: Other    Speed: Unknown    Error Correction Type: None    System Type: Unified    Associativity: 8-way Set-associative Handle 0x0007, DMI type 7, 19 bytes Cache Information    Socket Designation: L3-Cache    Configuration: Enabled, Not Socketed, Level 3    Operational Mode: Varies With Memory Address    Location: Internal    Installed Size: 3072 kB    Maximum Size: 3072 kB    Supported SRAM Types:       Other    Installed SRAM Type: Other    Speed: Unknown    Error Correction Type: None    System Type: Unified    Associativity: Other Handle 0x0008, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J1A1    Internal Connector Type: None    External Reference Designator: PS2Mouse    External Connector Type: PS/2    Port Type: Mouse Port Handle 0x0009, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J1A1    Internal Connector Type: None    External Reference Designator: Keyboard    External Connector Type: PS/2    Port Type: Keyboard Port Handle 0x000A, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J2A2B    Internal Connector Type: None    External Reference Designator: Video    External Connector Type: DB-15 female    Port Type: Video Port Handle 0x000B, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J3A1    Internal Connector Type: None    External Reference Designator: USB1    External Connector Type: Access Bus (USB)    Port Type: USB Handle 0x000C, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J3A1    Internal Connector Type: None    External Reference Designator: USB2    External Connector Type: Access Bus (USB)    Port Type: USB Handle 0x000D, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J3A1    Internal Connector Type: None    External Reference Designator: USB3    External Connector Type: Access Bus (USB)    Port Type: USB Handle 0x000E, DMI type 8, 9 bytes Port Connector Information    Internal Reference Designator: J5A1    Internal Connector Type: None    External Reference Designator: LAN    External Connector Type: RJ-45    Port Type: Network Port Handle 0x000F, DMI type 9, 17 bytes System Slot Information    Designation: J6B2    Type: x16 PCI Express    Current Usage: In Use    Length: Long    ID: 0    Characteristics:       3.3 V is provided       Opening is shared       PME signal is supported    Bus Address: 0000:00:01.0 Handle 0x0010, DMI type 9, 17 bytes System Slot Information    Designation: J6B1    Type: x1 PCI Express    Current Usage: In Use    Length: Short    ID: 1    Characteristics:       3.3 V is provided       Opening is shared       PME signal is supported    Bus Address: 0000:00:1c.3 Handle 0x0012, DMI type 11, 5 bytes OEM Strings    String 1: Dell System    String 2: 5[0003]    String 3: 13[P18F] Handle 0x0013, DMI type 12, 5 bytes System Configuration Options    Option 1: To Be Filled By O.E.M. Handle 0x001C, DMI type 21, 7 bytes Built-in Pointing Device    Type: Touch Pad    Interface: Bus Mouse    Buttons: 2 Handle 0x001D, DMI type 22, 26 bytes Portable Battery    Location: Sys. Battery Bay    Manufacturer: Sanyo                Serial Number: 5390       Name: DELL 4YRJH22    Chemistry: Lithium Ion    Design Capacity: 45000 mWh    Design Voltage: 10800 mV    SBDS Version: 1.0                  Maximum Error: 2%    SBDS Manufacture Date: 2012-02-28    OEM-specific Information: 0x00000001 Handle 0x001E, DMI type 32, 20 bytes System Boot Information    Status: No errors detected Handle 0x0020, DMI type 27, 12 bytes Cooling Device    Type: Fan    Status: OK    OEM-specific Information: 0x00000000 Handle 0x0021, DMI type 28, 20 bytes Temperature Probe    Description: CPU Internal Temperature    Location: Processor    Status: OK    Maximum Value: 127.0 deg C    Minimum Value: 0.0 deg C    Resolution: 1.000 deg C    Tolerance: 0.5 deg C    Accuracy: Unknown    OEM-specific Information: 0x00000000 Handle 0xB000, DMI type 176, 5 bytes OEM-specific Type    Header and Data:       B0 05 00 B0 00 Handle 0xB100, DMI type 177, 12 bytes OEM-specific Type    Header and Data:       B1 0C 00 B1 1A 0E 00 00 00 00 00 00 Handle 0x0025, DMI type 209, 12 bytes OEM-specific Type    Header and Data:       D1 0C 25 00 00 00 00 03 05 01 00 03 Handle 0x0026, DMI type 210, 12 bytes OEM-specific Type    Header and Data:       D2 0C 26 00 00 00 00 03 05 20 01 03 Handle 0x0027, DMI type 211, 13 bytes OEM-specific Type    Header and Data:       D3 0D 27 00 01 00 00 00 00 02 03 04 04    Strings:       Front            Handle 0x0028, DMI type 212, 57 bytes OEM-specific Type    Header and Data:       D4 39 28 00 70 00 71 00 01 49 50 48 9C 00 49 FC       01 9B 00 49 FC 00 7F 01 4A FB 04 80 01 4A FB 00       53 01 4A F7 08 52 01 4A F7 08 7B 01 4A EF 10 7C       01 4A EF 10 FF FF 00 00 00 Handle 0x002A, DMI type 217, 8 bytes OEM-specific Type    Header and Data:       D9 08 2A 00 01 02 00 00    Strings:                                 Handle 0x002B, DMI type 219, 11 bytes OEM-specific Type    Header and Data:       DB 0B 2B 00 00 01 02 03 00 04 05    Strings:                                                                                     Handle 0x002C, DMI type 220, 22 bytes OEM-specific Type    Header and Data:       DC 16 2C 00 01 F0 00 00 02 F0 00 00 00 00 03 F0       04 F0 00 00 00 00 Handle 0x002D, DMI type 221, 19 bytes OEM-specific Type    Header and Data:       DD 13 2D 00 00 00 00 00 00 03 00 00 00 00 00 00       00 00 00 Handle 0x002E, DMI type 222, 16 bytes OEM-specific Type    Header and Data:       DE 10 2E 00 01 08 FF FF 00 00 00 00 00 00 00 00 Handle 0x0014, DMI type 16, 15 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 0x0016, DMI type 20, 19 bytes Memory Device Mapped Address    Starting Address: 0x00000000000    Ending Address: 0x000FFFFFFFF    Range Size: 4 GB    Physical Device Handle: 0x0015    Memory Array Mapped Address Handle: 0x0018    Partition Row Position: 1    Interleave Position: 1    Interleaved Data Depth: 1 Handle 0x0017, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: Unknown    Data Width: Unknown    Size: No Module Installed    Form Factor: DIMM    Set: None    Locator: DIMM_B    Bank Locator: BANK 2    Type: Unknown    Type Detail: None    Speed: Unknown    Manufacturer: Not Specified    Serial Number: Not Specified    Asset Tag: Not Specified    Part Number: Not Specified    Rank: Unknown Handle 0x0018, DMI type 19, 15 bytes Memory Array Mapped Address    Starting Address: 0x00000000000    Ending Address: 0x000FFFFFFFF    Range Size: 4 GB    Physical Array Handle: 0x0014    Partition Width: 2 Handle 0x002F, DMI type 13, 22 bytes BIOS Language Information    Language Description Format: Abbreviated    Installable Languages: 1       eng    Currently Installed Language: eng Handle 0x0030, DMI type 131, 64 bytes OEM-specific Type    Header and Data:       83 40 30 00 31 00 00 00 00 00 00 00 00 00 00 00       F8 00 4B 1C FF FF FF FF 01 00 00 00 00 00 07 00       AD 04 04 00 00 00 00 00 C8 00 FF FF 00 00 00 00       00 00 00 00 32 00 00 00 76 50 72 6F 00 00 00 00 Handle 0x0029, DMI type 216, 9 bytes OEM-specific Type    Header and Data:       D8 09 29 00 01 02 01 00 00    Strings:       INTEL       0000 Handle 0x0000, DMI type 0, 24 bytes BIOS Information    Vendor: Dell Inc.    Version: A05    Release Date: 08/03/2012    Address: 0xF0000    Runtime Size: 64 kB    ROM Size: 2048 kB    Characteristics:       MCA is supported       PCI is supported       BIOS is upgradeable       BIOS shadowing is allowed       ESCD support is available       Boot from CD is supported       Selectable boot is supported       BIOS ROM is socketed       EDD is supported       5.25"/1.2 MB floppy services are supported (int 13h)       3.5"/720 kB floppy services are supported (int 13h)       3.5"/2.88 MB floppy services are supported (int 13h)       Print screen service is supported (int 5h)       8042 keyboard services are supported (int 9h)       Serial services are supported (int 14h)       Printer services are supported (int 17h)       CGA/mono video services are supported (int 10h)       ACPI is supported       USB legacy is supported       ATAPI Zip drive boot is supported       BIOS boot specification is supported       Targeted content distribution is supported    BIOS Revision: 0.5    Firmware Revision: 0.5 Handle 0x0002, DMI type 2, 15 bytes Base Board Information    Manufacturer: Dell Inc.    Product Name: 01HXXJ    Version: A05    Serial Number: .JSQ7PA1.CN7117623M00J2.    Asset Tag: Not Specified    Features:       Board is a hosting board       Board is replaceable    Location In Chassis: To Be Filled By O.E.M.    Chassis Handle: 0x0003    Type: Motherboard    Contained Object Handles: 0 Handle 0x0003, DMI type 3, 21 bytes Chassis Information    Manufacturer: Dell Inc.    Type: Portable    Lock: Not Present    Version: Not Specified    Serial Number: JSR1    Asset Tag: Not Specified    Boot-up State: Safe    Power Supply State: Safe    Thermal State: Safe    Security Status: None    OEM Information: 0x00000000    Height: Unspecified    Number Of Power Cords: 1    Contained Elements: 0 Handle 0x0001, DMI type 1, 27 bytes System Information    Manufacturer: Dell Inc.    Product Name: Inspiron N5050    Version: Not Specified    Serial Number: JSR1    UUID: 4C4C4544-0053-5110-8029-CAC05241    Wake-up Type: Power Switch    SKU Number: To be filled by O.E.M.    Family:                      Handle 0x0024, DMI type 208, 12 bytes OEM-specific Type    Header and Data:       D0 0C 24 00 02 05 FE 00 04 05 01 02    Strings:       20120323       20120323 Handle 0x0011, DMI type 10, 6 bytes On Board Device Information    Type: Video    Status: Enabled    Description: Mobile Intel SandyBridge HD Graphics Handle 0x0015, DMI type 17, 28 bytes Memory Device    Array Handle: 0x0014    Error Information Handle: 0x0000    Total Width: 64 bits    Data Width: 64 bits    Size: 4096 MB    Form Factor: SODIMM    Set: None    Locator: DIMM_A    Bank Locator: BANK 0    Type: DDR3    Type Detail: Synchronous    Speed: 1067 MHz    Manufacturer: 014F    Serial Number: 0009F2    Asset Tag: 54114000       Part Number: JM1066-4G        Rank: Unknown Handle 0x0031, DMI type 127, 4 bytes End Of Table
That’s it. Happy weekend. Stay happy!