DDR3 Computer Memory Overview
DDR3 is the next-generation evolution of DDR and newer DDR2 memory technology that will break the Gigahertz speed barrier for memory speed.DDR3 memory comes with a promise of a power consumption reduction of 30% compared to current DDR2 modules, due to DDR3’s 1.5 V supply voltage, compared to DDR2’s 1.8 V or DDR-1’s 2.5 V. This supply voltage works well with the latest fabrication technology used for most DDR3 chips. Some manufacturers further propose to use “dual-gate” transistors to reduce leakage of current.
DDR3 is an industry standard technology defined by JEDEC, who is the semiconductor standardization body of the Electronic Industries Alliance. About 300 member companies representing every segment of the computer memory industry actively participate to develop standards to meet the industry needs.
DDR3 memory features higher data bandwidths, faster speeds, lower voltage and power consumption, and improved thermal performance. Lower power consumption will allow longer battery life for laptops. DDR3 memory is engineered to support the next-generation quad-processors that require higher data bandwidth to enable higher levels of performance.
The main benefit of DDR3 comes from the higher bandwidth made possible by DDR3’s 8 bit deep pre-fetch buffer, whereas DDR2’s is 4 bits, and DDR-1’s is 2 bits deep. Theoretically, these modules could transfer data at an effective clock rate of 800–1600 MHz (using both edges of a 400–800 MHz I/O clock), compared to DDR2’s current range of effective 400–800 MHz (200–400 MHz clock) or DDR-1’s range of 200–400 MHz (100–200 MHz). To date, such bandwidth requirements have been mainly found in the graphics market, where fast transfer of information between frames is required.
Prototypes were announced in early 2005, and products started appearing on the market as of mid-2007, in the form of motherboards based on Intel’s P35 “Bearlake” chipset and memory DIMMs at speeds up to DDR3 1600Mhz. DDR3 launched for these special Intel chipset-based desktops in July 2007, and notebook and server platforms will follow in 2008 and 2009. AMD’s roadmap shows they will also support DDR3 as the new memory technology continues its market ramp-up in 2008.
DDR3 memory modules come in 1066MHz, 1333MHz and 1600MHz speeds (data rate), with 1066MHz and 1333MHz DDR3 launched in 2007, with 1600MHz DDR3 expected in 2008. This compares with DDR2 speeds of 533MHz, 667MHz, and 800MHz.
DDR3 DIMMs have 240 pins, the same number as DDR2, and are the same size, but are electrically incompatible and have a different key notch location. This will keep end users from installing an incorrect part into a DDR2 or DDR3 motherboard.
GDDR3 memory, with a similar name but completely different technology, has already been in use for several years in high-end graphic cards such as ones from NVIDIA or ATI Technologies, and as main system memory on the Microsoft Xbox 360. It has sometimes been incorrectly referred to as “DDR3″.
DDR3 will be available on desktops, servers, notebooks, telecommunications/networking and other platforms in the following form-factors:
- Unbuffered DIMMs, ECC or non-ECC
- Registered ECC DIMMs
- MicroDIMMs
- SO-DIMMs
- Custom Modules