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The Info List - GDDR3



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GRAPHICS DDR3 SDRAM (G DDR3
DDR3
SDRAM) is a type of DDR SDRAM specialized for graphics processing units (GPUs) offering less access latency and greater device bandwidths. Originally designed by ATI Technologies , it has since been adopted as a JEDEC
JEDEC
standard.

CONTENTS

* 1 Overview * 2 Commercial implementation * 3 Advantages of G DDR3
DDR3
over DDR2 * 4 See also * 5 References * 6 External links

OVERVIEW

It has much the same technological base as DDR2 , but the power and heat dispersal requirements have been reduced somewhat, allowing for higher performance memory modules, and simplified cooling systems. G DDR3
DDR3
is not related to the JEDEC
JEDEC
DDR3
DDR3
specification. This memory uses internal terminators , enabling it to better handle certain graphics demands. To improve throughput, G DDR3
DDR3
memory transfers 4 bits of data per pin in 2 clock cycles .

The G DDR3
DDR3
Interface transfers two 32 bit wide data words per clock cycle from the I/O pins. Corresponding to the 4n-pre fetch a single write or read access consists of a 128 bit wide, one-clock-cycle data transfer at the internal memory core and four corresponding 32 bit wide, one-half-clock-cycle data transfers at the I/O Pins. Single-ended unidirectional Read and Write Data strobes are transmitted simultaneously with Read and Write data respectively in order to capture data properly at the receivers of both the Graphics SDRAM and the controller. Data strobes are organized per byte of the 32 bit wide interface.

COMMERCIAL IMPLEMENTATION

Despite being designed by ATI , the first card to use the technology was nVidia 's GeForce FX 5700 Ultra in early 2004, where it replaced the GDDR2
GDDR2
chips used up to that time. The next card to use G DDR3
DDR3
was nVidia's GeForce 6800 Ultra , where it was key in maintaining reasonable power requirements compared to the card's predecessor, the GeForce 5950 Ultra . ATI began using the memory on its Radeon X800 cards. G DDR3
DDR3
was Sony
Sony
's choice for the PlayStation 3 gaming console's graphics memory, although its nVidia based GPU is also capable of accessing the main system memory, which consists of XDR DRAM designed by Rambus Incorporated (Similar technology is marketed by nVidia as TurboCache in PC platform GPUs). Microsoft
Microsoft
's Xbox 360 has 512 MB of G DDR3
DDR3
memory. Nintendo
Nintendo
's Wii
Wii
also contains 64 MB of G DDR3
DDR3
memory.

ADVANTAGES OF G DDR3
DDR3
OVER DDR2

* GDDR3s strobe signal unlike DDR2 SDRAM
DDR2 SDRAM
is unidirectional ">

* ^ ATI Technologies Promotes GDDR3

* Gregory Agostinelli. "Method and Apparatus for fine tuning a memory interface". US PATENT OFFICE.