General Ubuntu Commands

1) How to check the type of RAM you have.

$ sudo dmidecode --type 17

Result should be like:

SMBIOS 2.7 present.

Handle 0x0008, DMI type 17, 21 bytes
Memory Device
    Array Handle: 0x0007
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 2048 MB
    Form Factor: SODIMM
    Set: None
    Locator: SODIMM1
    Bank Locator: Bank 0
    Type: DDR3
    Type Detail: Unknown

Handle 0x000A, DMI type 17, 21 bytes
Memory Device
    Array Handle: 0x0007
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: SODIMM
    Set: None
    Locator: SODIMM2
    Bank Locator: Bank 1
    Type: Unknown
    Type Detail: Unknown

2. Interesting website which tells you about your memory and other things.
crucial.com