DRAM

The kind of memory chip used for main memory: cheap and dense, so there can be many gigabytes of it, but slow to answer.

Dynamic random-access memory stores each bit as charge in a capacitor (one transistor and one capacitor per bit) that must be refreshed periodically; it is dense and cheap per byte but has an access latency of tens of nanoseconds at the chip and about 80-120 ns from a core's load.