Environment Info

• Ubuntu ver : Ubuntu 18.04.3 LTS
• Mother Board : SuperMicro C9X299-PG300F
• Initial RAM size : Total 16GB, one 16GB card at one slot
• RAM type : MTA16ATF2G64AZ-2G6E1

Current status

I am trying to add new RAM whose type is identical to the current RAM type. dmidecode command shows no added RAM and total number of memory array is 1 and each size is 16GB. So, free command outputs 16GB free size of memory.

Current RAM's slot is DIMMA1 and the new RAM of the same type is placed at the slot DIMMB1.

Question

How can I specify the right operation to be recognized by ubuntu or mother borad ?

Commands and their outputs that I tried

dmidecode

$ sudo dmidecode -t memory

# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 3.1.1 present.

Handle 0x001A, DMI type 16, 23 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: None
    Maximum Capacity: 1536 GB
    Error Information Handle: Not Provided
    Number Of Devices: 4

Handle 0x001B, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001A
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 16384 MB
    Form Factor: DIMM
    Set: None
    Locator: DIMMA1
    Bank Locator: P0_Node0_Channel0_Dimm0
    Type: DDR4
    Type Detail: Synchronous
    Speed: 2666 MT/s
    Manufacturer: Micron
    Serial Number: 1EE08861
    Asset Tag:  
    Part Number: 16ATF2G64AZ-2G6E1   
    Rank: 2
    Configured Clock Speed: 2666 MT/s
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x001C, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001A
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMA2
    Bank Locator: P0_Node0_Channel0_Dimm1
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x001D, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001A
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMB1
    Bank Locator: P0_Node0_Channel1_Dimm0
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x001E, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001A
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMB2
    Bank Locator: P0_Node0_Channel1_Dimm1
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x001F, DMI type 16, 23 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: None
    Maximum Capacity: 1536 GB
    Error Information Handle: Not Provided
    Number Of Devices: 4

Handle 0x0020, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001F
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMC1
    Bank Locator: P0_Node0_Channel2_Dimm0
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x0021, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001F
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMC2
    Bank Locator: P0_Node0_Channel2_Dimm1
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x0022, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001F
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMD1
    Bank Locator: P0_Node0_Channel3_Dimm0
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

Handle 0x0023, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x001F
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMMD2
    Bank Locator: P0_Node0_Channel3_Dimm1
    Type: Unknown
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: NO DIMM
    Serial Number: NO DIMM
    Asset Tag:  
    Part Number: NO DIMM
    Rank: Unknown
    Configured Clock Speed: Unknown
    Minimum Voltage: 1.2 V
    Maximum Voltage: 1.2 V
    Configured Voltage: 1.2 V

free

$ free -m 
              total        used        free      shared  buff/cache   available
Mem:          15710        1827       12570          50        1312       13505
Swap:         15624           0       15624