Ram type & speed

[AnupamMitra]

The OS in one of my desktops is Ubuntu 18.04.5 32 bit. RAM is 2 GB. Now I would like to upgrade to Ubuntu 20.04. Processor [Pentium(R) Dual-Core CPU E5200 @ 2.50GHz × 2]
which is, I think, okay for 64 bit. Graphics is Intel® G33 x86/MMX/SSE2. However the RAM is too low. Therefore, I would like to increase RAM. How do I know the required speed of RAM commensurate with my PC for buying additional Memory?

However, the output of dmidecode -t 17 is as under.

naresh@naresh-G31T-M2:~$ sudo dmidecode -t 17
[sudo] password for naresh: 
# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 2.5 present.

Handle 0x000F, DMI type 17, 27 bytes
Memory Device
    Array Handle: 0x000D
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 2048 MB
    Form Factor: DIMM
    Set: None
    Locator: DIMM0
    Bank Locator: BANK0
    Type: SDRAM
    Type Detail: Synchronous
    Speed: Unknown
    Manufacturer: Manufacturer0
    Serial Number: SerNum0
    Asset Tag: AssetTagNum0
    Part Number: PartNum0

Handle 0x0011, DMI type 17, 27 bytes
Memory Device
    Array Handle: 0x000D
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: DIMM1
    Bank Locator: BANK1
    Type: Unknown
    Type Detail: Unknown
    Speed: Unknown
    Manufacturer: Manufacturer1
    Serial Number: SerNum1
    Asset Tag: AssetTagNum1
    Part Number: PartNum1

naresh@naresh-G31T-M2:~$