Dynamic RAM (DRAM) is a type of semiconductor memory that uses capacitors to store the bits. The charging and discharging of the capacitor represents 0 and 1 i.e. the two possible values that can be stored in a bit.
The DRAM is a volatile memory i.e. the data in memory is lost when power is switched off. However, it still displays some data remanence. DRAM is low cost compared to SRAM so it is primarily used in main memory.
The following displays a DRAM:
This was the first type of DRAM in use but was gradually replaced by synchronous DRAM. This was called asynchronous because the memory access was not synchronized with the system clock.
This DRAM replaced the asynchronous RAM and is used in most computer systems today. In synchronous DRAM, the clock is synchronised with the memory interface. All the signals are processed on the rising edge of the clock.
There are many graphics related tasks that can be accomplished with both synchronous and asynchronous DRAM. Some of the DRAM used for these tasks are Video DRAM, Window DRAM, Multibank DRAM etc.
There are many differences between DRAM and SRAM. Some of these are given as follows: