DRAM (Dynamic Random Access Memory)
DRAM uses only a single capacitor per bit of data and so costs far less than SRAM, but it has many disadvantages. The DRAM memory registers require periodic refreshing every few milliseconds, during which the processor can't access the RAM (This time of refreshing is called the wait state). Refreshing causes DRAM to be slower than SRAM. Also, DRAM uses more power than SRAM. Despite this, DRAM became the primary system RAM in all computers for many years (all because it cost less to the dudes in charge). DRAM came in two varieties: Fast Page Mode (FPM) and Extended Data Out (EDO).