SimpleTech 256MB Module

DDR (double data rate) SDRAM is next-generation SDRAM technology that pushes the envelope of memory bandwidth and performance. DDR memory transports data at both the rising and falling edge of the clock signal, resulting in data transfer rates that are twice the frequency of the bus clock. So with a 100MHz or 133MHz memory bus clock, DDR memory yields an effective data rate of 200MHz and 266MHz respectively. In comparing a 133MHz front side bus (FSB) system, a PC2100 module, comprised of DDR266MHz components, has a peak bandwidth of 2.1GB/s versus a normal PC133 SDRAM module with a peak bandwidth of 1.05GB/s. Similarly, in a 100MHz FSB system, a PC1600 module, comprised of DDR200MHz components, has a peak bandwidth of 1.6GB/s compared to a PC100 SDRAM module with a peak bandwidth of 0.8GB/s. DDR memory also offers lower power consumption over SDRAM, operating at just 2.5V as opposed to 3.3V. DDR memory requires DDR enabled hardware, differing in having one notch and 184-pins while SDRAM has two notches and 168-pins.