RAM

The Commodore 64 had 64kb (65536 bytes) of RAM (Random Access Memory). The amount of RAM in the computer is acrually where the 64 in 'Commodore 64' came from. On startup, the C64 allocates 38,911 bytes (approx. 39kb) of RAM to Commodore Basic.

Types of RAM
The Commodore 64 has several different types of RAM. First is DRAM, Dynamic RAM which is the main RAM and is refreshed every few milliseconds. Then there is the SRAM, Static RAM which does not need constant refreshing.

Expansion packs
The RAM of the C64 can be expanded with cartridges. The first being REU, very famous and was developed by Commodore and there is also GeoRAM, an expansion pack designed for use with the GEOS operating system.