DDR SDRAM

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DDR SDRAM or double-data-rate synchronous dynamic random access memory is a type of memory integrated circuit used in computers. It achieves greater bandwidth than ordinary SDRAM by transferring data on both the rising and falling edges of the clock signal (double pumped). This effectively nearly doubles the transfer rate without increasing the frequency of the front side bus. Thus a 100 MHz DDR system has an effective clock rate of 200 MHz when compared to equivalent SDR SDRAM, the ?SDR? being a retroactive designation.

Related Topics:
Dynamic random access memory - Integrated circuit - Computer - Bandwidth - SDRAM - Double pumped - Transfer rate - Front side bus - MHz - Clock rate

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With data being transferred 8 bytes at a time DDR RAM gives a transfer rate of (memory bus clock rate) × 2 (for dual rate) × 8 (number of bytes transferred). Thus with a bus frequency of 100 MHz, DDR-SDRAM gives a max transfer rate of 1600 MB/s.

Related Topics:
Byte - MB - S

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JEDEC has set standards for speeds of DDR SDRAM, divided into two parts: The first specification is for memory chips and the second is for memory modules.

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