"DRAM potřebuje periodické obnovování, protože je nevolatilní a data v ní vydrží jen chvíli, takže musí být periodicky načtena a znovu zapsána. "
"Volatile memory, in contrast to non-volatile memory, is computer memory that requires power to maintain the stored information; it retains its contents while powered on but when the power is interrupted, the stored data is quickly lost."
https://en.wikipedia.org/wiki/Volatile_memory