Dynamic RAM must be refreshed thousands of times per second to maintain its memory contents, while static RAM does not need to be refreshed but is more expensive. Both types of RAM are volatile and will lose their stored data when a computer shuts down. The most important specifications of RAM are its storage capacity in bytes, megabytes, or gigabytes, and its speed in transferring data to the microprocessor, usually measured in hertz, megahertz, or gigahertz.

2. Dynamic RAM needs to be refreshed thousands of
times per second while static RAM need not be
updated, so, although it is also more expensive
faster. Both types of RAM are volatile, they lose
their contents when the computer shuts down.
The most important data from the RAM is the
storage capacity you have (Bytes, Megabytes,
Gigabytes, etc.) and the speed with which sends the
data to the micro for this process and is usually
expressed in hertz (megahertz, Gigahertios, etc).