DRAM

wikipedia:DRAM

The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge.

See also

• Memory: RAM, DRAM, SDRAM, NVRAM, DMA, ECC, VRAM, Nanya, SGRAM, DDR