From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
Double Data Rate Random Access Memory
DDR
DDR-RAM
DDR-SDRAM
Double Data Rate Synchronous Random Access Memory
<storage> (DDR-RAM, DDR-SDRAM ...Synchronous...) RAM that
transfers data on both 0-1 and 1-0 clock transitions,
theoretically yielding twice the data transfer rate of normal
RAM or SDRAM.
{DDR-RAM Article
(http://pcreview.co.uk/Article.php?aid=9)}.
{DDR-SDRAM Article
(http://www4.tomshardware.com/mainboard/00q4/001030/)}.
(2001-05-24)