How to find serial number and other hardware details of Laptop/PC/Server from command line using dmidecode

Whether you are checking your hardware's  warranty or trying to raise a support ticket, the first thing your hardware vendor will ask is the serial number and model name of your your Laptop/PC/Server. In most cases a laptop's serial number is printed at the bottom and for a  PC or a Server, it will be located at the rear side. But what if the serial number printed is tampered or faded. What if the machine is located in a remote location. In such situations we use dmidecode command to obtain the hardware details.

dmidecode is a command used to display a system's hardware components along with other important informations like serial number and version numbers. All these informations regarding a system is stored in tables called DMI. dmidecode command decodes the data inside the DMI tables and displays them in human readable format. The syntax for dmidecode is

dmidecode [options]

Running dmidecode without any option will dump the entire DMI table data in a human readable format. To view tht dmidecode output of a machine, execute

dmidecode

Sample Output:

# dmidecode 2.11
SMBIOS 2.7 present.
36 structures occupying 1904 bytes.
Table at 0x000E6E60.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
        Vendor: Insyde Corp.
        Version: V2.13
        Release Date: 11/13/2012
        Address: 0xE0000
        Runtime Size: 128 kB
        ROM Size: 4096 kB
        Characteristics:
                PCI is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                Boot from CD is supported
                Selectable boot is supported
                EDD is supported
                Japanese floppy for NEC 9800 1.2 MB is supported (int 13h)
                Japanese floppy for Toshiba 1.2 MB is supported (int 13h)
                5.25"/360 kB floppy services are supported (int 13h)
                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)
                8042 keyboard services are supported (int 9h)
                CGA/mono video services are supported (int 10h)
                ACPI is supported
                USB legacy is supported
                BIOS boot specification is supported
                Targeted content distribution is supported
                UEFI is supported
        BIOS Revision: 0.0
        Firmware Revision: 0.0

Handle 0x0001, DMI type 1, 27 bytes
System Information
        Manufacturer: Acer
        Product Name: TravelMate P243
        Version: V2.13
        Serial Number: NXV7BSI0803020BE3D7600
        UUID: 84A3F928-2AB0-C048-869A-089E017C287B
        Wake-up Type: Power Switch
        SKU Number: TravelMate P243_0721_2_13
        Family: Type1Family

Handle 0x0002, DMI type 2, 16 bytes
Base Board Information
        Manufacturer: Acer
        Product Name: BA40_HC
        Version: Type2 - A01 Board Version
        Serial Number: NBV7B110013020BE3D7600
        Asset Tag: Type2 - Board Asset Tag
        Features:
                Board is a hosting board
                Board is replaceable
        Location In Chassis: Type2 - Board Chassis Location
        Chassis Handle: 0x0003
        Type: Motherboard
        Contained Object Handles: 0

Handle 0x0003, DMI type 3, 23 bytes
Chassis Information
        Manufacturer: Chassis Manufacturer
        Type: Notebook
        Lock: Not Present
        Version: Chassis Version
        Serial Number: Chassis Serial Number
        Asset Tag:                                
        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
        SKU Number: Not Specified

Handle 0x0004, DMI type 4, 42 bytes
Processor Information
        Socket Designation: U3E1
        Type: Central Processor
        Family: Core i3
        Manufacturer: Intel(R) Corporation
        ID: A7 06 02 00 FF FB EB BF
        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) i3-2348M CPU @ 2.30GHz
        Voltage: 1.1 V
        External Clock: 100 MHz
        Max Speed: 4000 MHz
        Current Speed: 2300 MHz
        Status: Populated, Enabled
        Upgrade: Socket rPGA988B
        L1 Cache Handle: 0x0009
        L2 Cache Handle: 0x000A
        L3 Cache Handle: 0x000B
        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: 2
        Thread Count: 4
        Characteristics:
                64-bit capable
                Multi-Core
                Hardware Thread
                Execute Protection
                Enhanced Virtualization
                Power/Performance Control

Handle 0x0005, DMI type 5, 20 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
        Maximum Total Memory Size: 16384 MB
        Supported Speeds:
                Other
        Supported Memory Types:
                Other
        Memory Module Voltage: Unknown
        Associated Memory Slots: 2
                0x0006
                0x0007
        Enabled Error Correcting Capabilities:
                None

Handle 0x0006, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: DIMM0
        Bank Connections: None
        Current Speed: Unknown
        Type: DIMM
        Installed Size: Not Installed
                Enabled Size: Not Installed
        Error Status: OK

Handle 0x0007, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: DIMM1
        Bank Connections: None
        Current Speed: Unknown
        Type: DIMM
        Installed Size: 2048 MB (Single-bank Connection)
        Enabled Size: 2048 MB (Single-bank Connection)
        Error Status: OK

Handle 0x0008, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L1 Cache
        Configuration: Enabled, Not Socketed, Level 1
        Operational Mode: Write Through
        Location: Internal
        Installed Size: 32 kB
        Maximum Size: 32 kB
        Supported SRAM Types:
                Unknown
        Installed SRAM Type: Unknown
        Speed: Unknown
        Error Correction Type: Parity
        System Type: Data
        Associativity: 8-way Set-associative

Handle 0x0009, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L1 Cache
        Configuration: Enabled, Not Socketed, Level 1
        Operational Mode: Write Through
        Location: Internal
        Installed Size: 32 kB
        Maximum Size: 32 kB
        Supported SRAM Types:
                Unknown
        Installed SRAM Type: Unknown
        Speed: Unknown
        Error Correction Type: Parity
                System Type: Instruction
        Associativity: 8-way Set-associative

Handle 0x000A, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L2 Cache
        Configuration: Enabled, Not Socketed, Level 2
        Operational Mode: Write Through
        Location: Internal
        Installed Size: 256 kB
        Maximum Size: 256 kB
        Supported SRAM Types:
                Unknown
        Installed SRAM Type: Unknown
        Speed: Unknown
        Error Correction Type: Multi-bit ECC
        System Type: Unified
        Associativity: 8-way Set-associative

Handle 0x000B, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L3 Cache
        Configuration: Enabled, Not Socketed, Level 3
        Operational Mode: Write Back
        Location: Internal
        Installed Size: 3072 kB
        Maximum Size: 3072 kB
        Supported SRAM Types:
                Unknown
        Installed SRAM Type: Unknown
        Speed: Unknown
        Error Correction Type: Multi-bit ECC
        System Type: Unified
        Associativity: 12-way Set-associative

Handle 0x000C, DMI type 9, 17 bytes
System Slot Information
        Designation: J5C1
        Type: x16 PCI Express x16
        Current Usage: Available
        Length: Other
        ID: 1
                Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:01.0

Handle 0x000D, DMI type 9, 17 bytes
System Slot Information
        Designation: J6C1
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 2
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.0

Handle 0x000E, DMI type 9, 17 bytes
System Slot Information
        Designation: J6C2
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 3
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.1

Handle 0x000F, DMI type 9, 17 bytes
System Slot Information
        Designation: J6D2
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 4
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.2

Handle 0x0010, DMI type 9, 17 bytes
System Slot Information
        Designation: J7C1
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 5
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.3

Handle 0x0011, DMI type 9, 17 bytes
System Slot Information
        Designation: J7D2
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 6
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.4

Handle 0x0012, DMI type 9, 17 bytes
System Slot Information
        Designation: J8C1
        Type: x1 PCI Express x1
        Current Usage: Available
        Length: Other
        ID: 7
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.5

Handle 0x0013, DMI type 9, 17 bytes
System Slot Information
        Designation: J8C2
        Type: x16 PCI Express x16
        Current Usage: Available
        Length: Other
        ID: 8
        Characteristics:
                PME signal is supported
                Hot-plug devices are supported
        Bus Address: 0000:00:1c.7

Handle 0x0014, DMI type 10, 6 bytes
On Board Device Information
        Type: Video
        Status: Enabled
        Description: Video Graphics Controller

Handle 0x0015, DMI type 10, 6 bytes
On Board Device Information
        Type: Ethernet
        Status: Enabled
        Description: Realtek Lan Controller

Handle 0x0016, DMI type 11, 5 bytes
OEM Strings
        String 1: String1 for Original Equipment Manufacturer
        String 2: ijKjHfvkDABpB
        String 3: HEJWqdBnGgkWW
        String 4: 6YJYU+1CKvlMM
        String 5: String5 for Original Equipment Manufacturer

Handle 0x0017, DMI type 12, 5 bytes
System Configuration Options
        Option 1: SMI:00B2C002
        Option 2: String2 for Type12 Equipment Manufacturer
        Option 3: DSN: WD-WXD1E72HUH62
        Option 4: DSN:90301D4388G0NS-CG
        Option 5: DSN:0000
        Option 6: String6 for Type12 Equipment Manufacturer
        Option 7: String7 for Type12 Equipment Manufacturer

Handle 0x0018, DMI type 13, 22 bytes
BIOS Language Information
        Language Description Format: Long
        Installable Languages: 1
                en|US|iso8859-1
        Currently Installed Language: en|US|iso8859-1

Handle 0x0019, 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 0x001A, DMI type 17, 34 bytes
Memory Device
        Array Handle: 0x0019
        Error Information Handle: Not Provided
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: None
        Locator: DIMM0
        Bank Locator: BANK 0
        Type: Unknown
        Type Detail: Unknown
        Speed: Unknown
        Manufacturer: Empty
        Serial Number: Empty
        Asset Tag: Unknown
        Part Number: Empty
        Rank: Unknown
        Configured Clock Speed: Unknown

Handle 0x001B, DMI type 17, 34 bytes
Memory Device
        Array Handle: 0x0019
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: SODIMM
        Set: None
        Locator: DIMM1
        Bank Locator: BANK 2
        Type: DDR3
                Type Detail: Synchronous
        Speed: 1333 MHz
        Manufacturer: Nanya Technology
        Serial Number: 90301D43
        Asset Tag: Unknown
        Part Number: NT2GC64B88G0NS-CG
        Rank: 1
        Configured Clock Speed: 1333 MHz

Handle 0x001C, DMI type 19, 31 bytes
Memory Array Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x0007FFFFFFF
        Range Size: 2 GB
        Physical Array Handle: 0x0019
        Partition Width: 2

Handle 0x001D, DMI type 20, 35 bytes
Memory Device Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x0007FFFFFFF
        Range Size: 2 GB
        Physical Device Handle: 0x001B
        Memory Array Mapped Address Handle: 0x001C
        Partition Row Position: Unknown
        Interleave Position: 2
        Interleaved Data Depth: 1

Handle 0x001E, DMI type 131, 64 bytes
OEM-specific Type
        Header and Data:
                83 40 1E 00 31 00 00 00 00 00 00 00 00 00 00 00
                F8 00 57 1E FF FF FF FF 01 20 00 00 01 00 08 00
                E0 04 00 00 00 00 00 00 C8 00 FF FF 00 00 00 05
                8E 08 00 00 26 00 00 00 76 50 72 6F 00 00 00 00

Handle 0x001F, DMI type 170, 74 bytes
OEM-specific Type
        Header and Data:
                AA 4A 1F 00 01 48 00 00 7F 00 0F 00 06 00 01 02
                01 08 02 01 00 40 41 02 01 00 42 02 02 00 43 02
                04 00 44 02 08 00 45 02 10 00 46 02 20 00 47 02
        Partition Row Position: Unknown
        Interleave Position: 2
        Interleaved Data Depth: 1

Handle 0x001E, DMI type 131, 64 bytes
OEM-specific Type
        Header and Data:
                83 40 1E 00 31 00 00 00 00 00 00 00 00 00 00 00
                F8 00 57 1E FF FF FF FF 01 20 00 00 01 00 08 00
                E0 04 00 00 00 00 00 00 C8 00 FF FF 00 00 00 05
                8E 08 00 00 26 00 00 00 76 50 72 6F 00 00 00 00

Handle 0x001F, DMI type 170, 74 bytes
OEM-specific Type
        Header and Data:
                AA 4A 1F 00 01 48 00 00 7F 00 0F 00 06 00 01 02
                01 08 02 01 00 40 41 02 01 00 42 02 02 00 43 02
                04 00 44 02 08 00 45 02 10 00 46 02 20 00 47 02
                40 00 61 02 01 00 62 02 02 00 63 02 04 00 64 02
                08 00 82 02 02 00 83 02 04 00

Handle 0x0020, DMI type 171, 39 bytes
OEM-specific Type
        Header and Data:
                AB 27 20 00 01 86 80 16 01 02 EC 10 68 81 03 EC
                10 89 52 04 CF 1B 18 2C 05 86 80 20 1E 07 86 80
                8E 08 08 87 80 DA 07

Handle 0x0021, DMI type 172, 24 bytes
OEM-specific Type
        Header and Data:
                AC 18 21 00 02 14 01 FF 00 02 01 00 03 FF 00 04
                01 00 05 0F 00 06 FF 00

Handle 0x0022, DMI type 173, 9 bytes
OEM-specific Type
        Header and Data:
                AD 09 22 00 01 01 00 00 00

Handle 0x0023, DMI type 127, 4 bytes
End Of Table

In the above output we can see man records, each containing 

a handle value	–	Unique record identifier (eg: Handle 0x0000)
a DMI type	–	representing the type of record (eg: BIOS, System …)
size	–	size of each record
decoded value	–	multiple lines containing human readable data of    each record

Instead dumping entire data we can view the data regarding a specific record or a DMI type. Each DMI type can be represented by a number and a keyword. The below table displays different DMI type ids and their coreesponding information

DMI Type	Information
0	BIOS
1	System
2	Baseboard
3	Chassis
4	Processor
5	Memory Controller
6	Memory Module
7	Cache
8	Port Connector
9	System Slots
10	On Board Devices
11	OEM Strings
12	System Configuration Options
13	BIOS Language
14	Group Associations
15	System Event Log
16	Physical Memory Array
17	Memory Device
18	32-bit Memory Error
19	Memory Array Mapped Address
20	Memory Device Mapped Address
21	Built-in Pointing Device
22	Portable Battery
23	System Reset
24	Hardware Security
25	System Power Controls
26	Voltage Probe
27	Cooling Device
28	Temperature Probe
29	Electrical Current Probe
30	Out-of-band Remote Access
31	Boot Integrity Services
32	System Boot
33	64-bit Memory Error
34	Management Device
35	Management Device Component
36	Management Device Threshold Data
37	Memory Channel
38	IPMI Device
39	Power Supply
40	Additional Information
41	Onboard Devices Extended Information
42	Management Controller Host Interface

  In addition to the DMI type id there are keywords like

• bios (type - 0, 13)  
• system (type - 1, 12, 15, 23, 32)
• baseboard (type - 2, 10, 41)
• chassis (type - 3)
• processor (type - 4)
• memory (type - 5, 6, 16, 17)
• cache (type - 7)
• connector (type - 8)
• slot (type - 9)

Now lets see how to view individual/multiple records

#1)  To display the System informations like Serial Number, make and model of the machine, execute
 

dmidecode -t 1

Sample Output:

Handle 0x0001, DMI type 1, 27 bytes
System Information
    Manufacturer: LENOVO
    Product Name: 20354
    Version: Lenovo Z50-70
    Serial Number: 1031700601373
    UUID: 3FF1888E-0588-11E4-A818-28D244B4396A
    Wake-up Type: Power Switch
    SKU Number: LENOVO_MT_20354_BU_idea_FM_Lenovo Z50-70
    Family: IDEAPAD

From the above output we can find details of the system such as make, model, version, serial number etc... If you want to view the Serial Number alone, execute dmidecode with grep command

dmidecode -t 1|grep 'Serial Number

Sample Output:

    Serial Number: 1031700601373

#2) To find the chassis details of a server/system, execute

dmidecode -t 1

Sample Output:

Handle 0x0300, DMI type 3, 21 bytes
Chassis Information
        Manufacturer: Dell Inc.
        Type: Rack Mount Chassis
        Lock: Present
        Version: Not Specified
        Serial Number: C71332S
        Asset Tag: Not Specified
        Boot-up State: Safe
        Power Supply State: Safe
        Thermal State: Safe
        Security Status: Unknown
        OEM Information: 0x00000000
        Height: 4 U
        Number Of Power Cords: Unspecified
        Contained Elements: 0

The above details is the chassis information of a DELL server. In this record you can find make, type,serial number, form factor and status of power supply, thermal and boot-up states.

#3) To find the baseboard details, execute

dmidecode -t baseboard

Sample Output:

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
    Manufacturer: Intel Corporation
    Product Name: DG31PR
    Version: AAD97573-303
    Serial Number: BTPR9070032N
    Asset Tag: To be filled by O.E.M.
    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 0x001C, DMI type 10, 6 bytes
On Board Device Information
    Type: Video
    Status: Disabled
    Description:   Intel(R) Extreme Graphics 3 Controller

Handle 0x001D, DMI type 10, 6 bytes
On Board Device Information
    Type: Sound
    Status: Disabled
    Description:  Intel(R) Azalia Audio Device

Handle 0x001E, DMI type 10, 6 bytes
On Board Device Information
    Type: Ethernet
    Status: Disabled
    Description:         Intel (R) 82562 Ethernet Device.

The above output is the baseboard information of a P.C. Here we used the keyword (baseboard) instead of the DMI id. From the output we can say that the PC is installed with Intel DG31PR motherboard.The output also displays the information regarding the On Board Devices for Video, Sound and Ethernet.

#4) To find details of the processor installed, execute

dmidecode -t processor

Sample Output:

Handle 0x0008, DMI type 4, 32 bytes
Processor Information
    Socket Designation: Socket 1 CPU 1
    Type: Central Processor
    Family: Xeon
    Manufacturer: GenuineIntel
    ID: 43 0F 00 00 01 03 00 00
    Signature: Type 0, Family 15, Model 4, Stepping 3
    Flags:
        FPU (Floating-point unit on-chip)
        CX8 (CMPXCHG8 instruction supported)
        APIC (On-chip APIC hardware supported)
    Version: Intel Xeon
    Voltage: 1.5 V
    External Clock: 200 MHz
    Max Speed: 4000 MHz
    Current Speed: 3400 MHz
    Status: Populated, Enabled
    Upgrade: ZIF Socket
    L1 Cache Handle: 0x0004
    L2 Cache Handle: 0x0005
    L3 Cache Handle: Not Provided

Handle 0x0009, DMI type 4, 32 bytes
Processor Information
    Socket Designation: Socket 2 CPU 2
    Type: Unknown
    Family: Unknown
    Manufacturer: Not Specified
    ID: 00 00 00 00 00 00 00 00
    Version: Not Specified
    Voltage: 1.5 V
    External Clock: 200 MHz
    Max Speed: 4000 MHz
    Current Speed: 3400 MHz
    Status: Unpopulated
    Upgrade: ZIF Socket
    L1 Cache Handle: 0x0006
    L2 Cache Handle: 0x0007
    L3 Cache Handle: Not Provided.

 #5) To find details of the system memory array like Maximum memory capacity and device supported by the system, execute

dmidecode -t 16

Sample Output:

Handle 0x1000, DMI type 16, 15 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: Single-bit ECC
    Maximum Capacity: 32 GB
    Error Information Handle: Not Provided
    Number Of Devices: 8

From the above dmidecode output we can say that  the maximum physical memory supported by the system is 32 GB and we can install upto 8 memory module in the system

#6) To find the details of each memory module installed, execute

dmidecode -t 16

Sample Output:

Handle 0x1100, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: FB-DIMM
        Set: 1
        Locator: DIMM 1A
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: 667 MHz (1.5 ns)

Handle 0x1101, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: FB-DIMM
        Set: 3
        Locator: DIMM 2C
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: 667 MHz (1.5 ns)

Handle 0x1102, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: FB-DIMM
        Set: 1
        Locator: DIMM 3A
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: 667 MHz (1.5 ns)

Handle 0x1103, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: FB-DIMM
        Set: 3
        Locator: DIMM 4C
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: 667 MHz (1.5 ns)

Handle 0x1104, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: No Module Installed
        Form Factor: FB-DIMM
        Set: 2
        Locator: DIMM 5B
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: Unknown

Handle 0x1105, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: No Module Installed
        Form Factor: FB-DIMM
        Set: 4
        Locator: DIMM 6D
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: Unknown

Handle 0x1106, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: No Module Installed
        Form Factor: FB-DIMM
        Set: 2
        Locator: DIMM 7B
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: Unknown

Handle 0x1107, DMI type 17, 23 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: No Module Installed
        Form Factor: FB-DIMM
        Set: 4
        Locator: DIMM 8D
        Bank Locator: Not Specified
        Type: DDR2 FB-DIMM
        Type Detail: Synchronous
        Speed: Unknown.

In the above output we could see 8 records represent 8 memory slots and their corresponding details. If you check closely  you can see that  in some records Size (memory size) is shown as 4096 MB (4 GB) and in some cases it is shown as 'No Module Installed'. i.e no memory is installed in the slots represented by the corresponding records. To view the Size of memory modules installed in each slot run dmidecode with grep command as displayed below

dmidecode -t 17|grep Size

Sample Output:

    Size: 4096 MB
    Size: 4096 MB
    Size: 4096 MB
    Size: 4096 MB
    Size: No Module Installed
    Size: No Module Installed
    Size: No Module Installed
    Size: No Module Installed

 From the above output we can say that out of 8 memory slots only 4 is installed and others blank. The total available memory in this machine is  16384 MB(16 GB) out of a possible 32 GB.
For more details on dmidecode check the man pages.