DDR SDRAM ( sometimes referred to as DDR1 SDRAM ) has been superseded by DDR2 SDRAM and DDR3 SDRAM, neither of which is either forward or backward compatible with DDR SDRAM, meaning that DDR2 or DDR3 memory modules will not work in DDR-equipped motherboards, and vice versa.

SDRAM is widely used in computers ; from the original SDRAM, further generations of DDR ( or DDR1 ) and then DDR2 and DDR3 have entered the mass market, with DDR4 currently being designed and anticipated to be available in 2015.

JEDEC formally adopted its first SDRAM standard in 1993 and subsequently adopted other SDRAM standards, including those for DDR, DDR2 and DDR3 SDRAM.

* 200-pin SO-DIMM, used for DDR SDRAM and DDR2 SDRAM

Notch position between DDR and DDR2

The power consumption and voltage of DDR2 is significantly lower than DDR ( 1 ) at the same speed.

In addition to redesigning parts of the GPU, NVIDIA moved to a 256-bit memory data bus, allowing for significantly higher memory bandwidth than the 5800 even when utilizing more common DDR SDRAM instead of DDR2.

The Opteron processor possesses an integrated memory controller supporting DDR SDRAM, DDR2 SDRAM or DDR3 SDRAM ( depending on processor generation ).

DDR2 is neither forward nor backward compatible with either DDR or DDR3.

In addition to double pumping the data bus as in DDR SDRAM ( transferring data on the rising and falling edges of the bus clock signal ), DDR2 allows higher bus speed and requires lower power by running the internal clock at half the speed of the data bus.

Since the DDR2 internal clock runs at half the DDR external clock rate, DDR2 memory operating at the same external data bus clock rate as DDR results in DDR2 being able to provide the same bandwidth but with higher latency.

Alternatively, DDR2 memory operating at twice the external data bus clock rate as DDR may provide twice the bandwidth with the same latency.

The best-rated DDR2 memory modules are at least twice as fast as the best-rated DDR memory modules.

Like DDR before it, the DDR2 I / O buffer transfers data both on the rising and falling edges of the clock signal ( a technique called " double pumping ").

The key difference between DDR and DDR2 is that for DDR2 the memory cells are clocked at 1 quarter ( rather than half ) the rate of the bus.

It supersedes the original DDR SDRAM specification and has itself been superseded by DDR3 SDRAM.

The DDR2 prefetch buffer is 4 bits deep, whereas it is two bits deep for DDR and eight bits deep for DDR3.

Micron makes DRAM Memory components and modules, including SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, LPDRAM, RLDRAM, PSRAM, and multi-chip packages.

Comparison of 200-pin SO-DIMMs for DDR SDRAM, DDR2 SDRAM and DDR3 SDRAM for laptops PCs

* DDR SDRAM, DDR2 SDRAM, and DDR3 SDRAM which all use DDR signalling

Inotera ’ s main products are currently the 512Mb DDR, 512Mb DDR2, 1Gb DDR2 and 1Gb DDR3 products featuring high density, high speed, and low power consumption.

DDR3 does use the same electric signaling standard as DDR and DDR2, Stub Series Terminated Logic, albeit at different timings and voltages.

It was replaced by the Staatliche Luftfahrt-Inspektion der DDR ( Public Department of Aviation of the GDR ) on 1 Jan 1968, from which Luftfahrt-Bundesamt took over all operations and most of the staff on 4 October 1990, the day after German re-unification.

Tape is a linear method of storing information and since nearly all video recordings made nowadays are digital direct to disk recording ( DDR ), videotape is expected to gradually lose importance as non-linear / random-access methods of storing digital video data become more common.

On June 21, 1948 the Deutsche Mark ( German Mark ) was introduced by the Bank deutscher Länder in the western zones of occupation in Germany ; the Deutsche Emissions-and Girobank ( German bank of issue and giro centre ) of the Soviet zone followed suit on June 23, 1948, issuing its own Deutsche Mark ( colloquially referred to as the East German Mark or Ostmark ), later officially called " Mark der Deutschen Notenbank " ( 1964 – 1967 ) and then " Mark der DDR " ( 1968 – 1990 ), through to the adoption in reunified Germany of the euro in 1999, with Germany minting its own German euro coins and using the unified Euro banknotes used all over the Eurozone of the 21st century.

DDR uses existing Public Switched Telephone Network ( PSTN ) lines – or the network of all public circuit-switched telephone networks-to form a connection between the sender and receiver.

DDR uses a Point-to-Point Protocol ( PPP ) link, which handles all networking functions such as sending, receiving and compressing the signals between two computers on the internet.

Although the DDR interface is a virtual one, all of the configuration commands for physical interfaces are available.

When all data I / O signals are accounted, QDR SRAM is not 2x faster than DDR SRAM but is 100 % efficient when reads and writes are interleaved.

U-bahn maps in the Friedrichstraße transfer station were unique: they depicted all the Western lines but not the Geisterbahnhöfe, and showed the city divided into " Berlin, Hauptstadt der DDR " (" Berlin, capital of the German Democratic Republic ") and " Westberlin.

DDR Solo Bass Mix features 16 songs, all of which are new to Dance Dance Revolution.

DDR Festival is the first version of Dance Dance Revolution in Japan to primarily use Japanese for in-game text and menus, all DDR games before it simply used American English.

So the media controlled by the East German government emphasised the use of the official name, DDR, while West Germans, western media and statesmen may have used other names such as Middle Germany, emphasising the location of East Germany in the centre of pre-1937 Germany.

This is because the Reichsbahn was specifically mentioned in several postwar treaties and directives regarding the right to operate the railroad in West Berlin ; had the East German government changed the name of the railways to, for example, Staatsbahn der DDR ( State Railways of the GDR ), it would likely have lost this right.

It is also worth noting that these experiments would not have been possible without the support of John Klotz of DOD / DDR & E.

-DIMMs based on Double Data Rate ( DDR ) DRAM have data but not the strobe at double the rate of the clock.

While DDR SDRAM has typical read latencies of between 2 and 3 bus cycles, DDR2 may have read latencies between 4 and 6 cycles.

For example, the northbridge from the Nvidia nForce2 chipset will only work with Socket A processors combined with DDR SDRAM ; the Intel i875 chipset will only work with systems using Pentium 4 processors or Celeron processors that have a clock speed greater than 1. 3 GHz and utilize DDR SDRAM, and the Intel i915g chipset only works with the Intel Pentium 4 and the Celeron, but it can use DDR or DDR2 memory.

Although most commercial pads have four arrow panels ( DDR / In The Groove ), some have five ( Pump It Up ), six ( Dance Dance Revolution Solo 2000 ), eight ( Dance: UK ), ( MC Groovz Dance Craze ), or nine ( Technomotion ).

Some homebrew pads have extra features such as additional arrows ( for playing Pump It Up or DDR Solo ), menu switches and pushbuttons, and bars.

These are functionally equivalent to the previous generation, except they have a dual-channel DDR2 SDRAM memory controller which replaces the single-channel DDR SDRAM version.

Such memory cards have to be PlayStation ( not PS2 ) memory cards with Link Data from the home version of DDR 5th Mix ( the home version of 6thMix cannot create arcade-compatible Link Data ).

The game engine and menus have also been used in two North American versions of DDR, Dance Dance Revolution for the PC, and Dance Dance Revolution Konamix.

Such memory cards have to be PlayStation 1 ( not PS2 ) memory cards with Link Data from the home version of DDR 5th Mix ( the home version of DDRMAX2 cannot create arcade-compatible Link Data ).

* DROP OUT: the first DDR song to have a consistent BPM over 200.

Every songs from DDR Ultramix do not have Beginner difficulty, though some of their heavy charts have been replaced with a new, harder chart.

Due to global release of DDR since DDR SuperNOVA, starting from DDR SuperNOVA2, unlock codes can be use in unlocking hidden contents to those game centers that doesn't have e-amusement service in other countries.