Synchronous Dynamic Random Access Memory
SDRAM is a kind of memory integrated circuit used on the PC. This memory is synchronized by the clock present on its bus, hence its name (FPM, EDO and BEDO memories are asynchronous).
Its main advantage is its capability of reading sequential data fast, like FPM, EDO and BEDO memories, but faster than them. For example, supposing four data sequentially stored (four consecutive addresses) the first data can delay several clock cycles to be read (seven clock cycles, for example) but the following data can be read always using just one clock cycle. Because of this feature, it is said that this kind of memory has a x-1-1-1 access cycle (FPM cycle is of x-3-3-3, EDO is of x-2-2-2 and BEDO is of x-1-1-1).
This memory chip is found on memory modules called DIMM.
SDRAM memories are classified accordingly to the maximum clock rate they support: PC66, PC100 and PC133 (66 MHz, 100 MHz and 133 MHz, respectively).