qdr

QDR, in the context of computing hardware, most often stands for Quad Data Rate. It refers to a class of high-bandwidth SRAM (static random-access memory) devices designed to move data rapidly for performance-critical systems. The defining feature of QDR memory is the ability to transfer four data words per clock cycle, achieved by using a bidirectional data bus with two independent data ports and by transferring data on both the rising and the falling edges of the clock.

How it works: QDR memory typically employs two separate data ports and supports simultaneous reads and writes. This arrangement allows data to be moved on multiple edges of the clock, effectively increasing bandwidth without requiring extreme clock frequencies. The architecture is optimized for low latency and high sustained throughput, which makes it suitable for buffering and caching roles in demanding environments.

Applications and use: QDR SRAM is commonly used as high-bandwidth cache memory in networking equipment such as routers and switches, as well as in other performance-critical interconnects and accelerators. It is favored where fast access to large data blocks is more important than dense storage. QDR devices are available in several generations, including QDR, QDR II, and QDR II+, with later generations offering higher densities and improved power efficiency.

Disambiguation: The acronym QDR can have other meanings in different fields, but in the realm of computer memory it most often refers to Quad Data Rate SRAM. See also DDR SDRAM and SRAM for related technologies.