There are two different kinds of RAM, depending on the condition for storing the data: SRAM (Static RAM) and DRAM (Dynamic RAM).
The data contained in SRAM is maintained indefinitely, unless the backup battery power is too low.
On the other hand, data contained in DRAM is lost when the power is turned off. Because of this, you should always store any data residing in DRAM to a
memory card, floppy disk, or an external SCSI device before turning off the power.