How to find the frequency and type of my current RAM?

This should do:

sudo lshw -short -C memory

Use the lshw command with the memory class:

$ sudo lshw -C memory
  # Some things about firmware and caches
  *-memory
       description: System Memory
       physical id: 13
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: DIMM [empty]
          product: [Empty]
          vendor: [Empty]
          physical id: 0
          serial: [Empty]
          slot: ChannelA-DIMM0
     *-bank:1
          description: SODIMM DDR3 Synchronous 1600 MHz (0.6 ns)
          product: M471B5273DH0-CK0
          vendor: Samsung
          physical id: 1
          serial: 34A8C7AF
          slot: ChannelA-DIMM1
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     # More banks.

As you can see, I'm using DDR3 1600MHz RAM.

Another option is dmidecode:

$ sudo dmidecode -t memory
# dmidecode 2.9
SMBIOS 2.5 present.

Handle 0x003B, DMI type 16, 15 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: Multi-bit ECC
    Maximum Capacity: Unknown
    Error Information Handle: Not Provided
    Number Of Devices: 8

Handle 0x003D, DMI type 17, 27 bytes
Memory Device
    Array Handle: 0x003B
    Error Information Handle: Not Provided
    Total Width: 72 bits
    Data Width: 64 bits
    Size: 4096 MB
    Form Factor: DIMM
    Set: None
    Locator: DIMM_A1
    Bank Locator: NODE 0 CHANNEL 0 DIMM 0
    Type: Other
    Type Detail: Synchronous
    Speed: 1067 MHz (0.9 ns)
    Manufacturer: 0x0198
    Serial Number: 0xB12A9593
    Asset Tag: Unknown
    Part Number: 9965426-037.A00LF 
# more such devices

This is for a server with ECC memory (as can be seen from the Error Correction Type field and the difference between Data Width and Total Width).

Both tools are dependencies of the ubuntu-standard package and should be available by default on all Ubuntu systems. There used to be another tool called hwinfo, which is no longer available for Ubuntu since 13.10.

I could only get this info with dmidecode, but rather than grepping, it's cleaner to use the right type:

sudo dmidecode --type memory

This will give you all information you may want, probably:

sudo dmidecode | grep -A 15 Memory

Try Hard info, for install run in terminal : sudo apt-get install hardinfo It has interface, and it's simple to use. )

? REST OF ANSWERS

The rest of methods don't always work, reporting the speed as unknown. Here's one way that never fails.

? REQUIRED SOFTWARE

Install i2c-tools.

? MEMORY BANDWIDTH

Read the value from the RAM eeprom with:

sudo modprobe eeprom && decode-dimms | grep speed | rev | cut --delimiter=" " --fields=2,3 | rev; sudo modprobe --remove eeprom

The value is returned in MT/s.

? MEMORY FREQUENCY

If you want the value in MHz just divide the previous result by the number of channels the RAM module has, which you can get with:

sudo modprobe eeprom && decode-dimms | grep Ranks | rev | cut --delimiter=" " --fields=1 | rev; sudo modprobe --remove eeprom

? MISCONFIGURED MOTHERBOARD

Note this is the speed of the module, not the speed that the motherboard is configured and capable to use.

For checking if the speed is misconfigured in the motherboard access the BIOS or UEFI, as explained in your motherboard manual.

Above answers are correct; I just wanted to add further by piping the output of command to grep for Type and speed.

sudo dmidecode --type memory | grep -m2 Type

FYI: T in Type must be capital.

This might give either Type: DDR4 OR Type: DDR3

for speed use

sudo dmidecode --type memory | grep -m1 Speed

FYI: -m option of grep is used to limit the number of lines; for example -m2 means 2 lines.

Most of these answers will just give you the nominal clock speed of the memory. It may not be the actual clock speed.

The canonical method is to boot Memtest or if you are so endowed, boot Windows and use CPU-Z.

You can trust BIOS, you can trust Memtest. There are an enormous number of low cost boxes fitted with 1333MHz DDR3 that is actually clocked at 1066MHz. Both DMI decode and LSHW may be deceptive.