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Graphics DDR3 SDRAM
DDR3 SDRAM
(G DDR3
DDR3
SDRAM) is a type of DDR SDRAM
DDR SDRAM
specialized for graphics processing units (GPUs) offering less access latency and greater device bandwidths. Originally designed by ATI Technologies,[1] 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[edit] 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[edit] Despite being designed by ATI, the first card to use the technology was nVidia's GeForce FX
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's choice for the PlayStation 3
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
XDR DRAM
designed by Rambus Incorporated
Rambus Incorporated
(Similar technology is marketed by nVidia as TurboCache in PC platform GPUs). Microsoft's Xbox 360
Xbox 360
has 512 MB of G DDR3
DDR3
memory. Nintendo's Wii
Wii
also contains 64 MB of G DDR3
DDR3
memory. Advantages of G DDR3
DDR3
over DDR2[edit]

GDDR3s strobe signal unlike DDR2 SDRAM
DDR2 SDRAM
is unidirectional & single-ended (RDQS, WDQS). This means there is a separate read and write data strobe allowing for a quicker read to write ratio than DDR2. G DDR3
DDR3
has a hardware reset capability allowing it to flush all data from memory and then start again. Lower voltage requirements leads to lower power requirements, and lower heat output. Higher clock frequencies, due to lower heat output, this is beneficial for increased throughput and more precise timings.

See also[edit]

List of device bandwidths

References[edit]

^ ATI Technologies
ATI Technologies
Promotes GDDR3

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

External links[edit]

JEDEC
JEDEC
Standard 3.11.5.7 - G DDR3
DDR3
Specific SGRAM
SGRAM
Functions

v t e

Dynamic random-access memory
Dynamic random-access memory
(DRAM)

Asynchronous

FPM RAM EDO RAM

Synchronous

SDRAM Fast Cycle DRAM (FCRAM) RLDRAM DDR SDRAM Mobile DDR
Mobile DDR
(LPDDR) DDR2 SDRAM DDR3
DDR3
SDRAM DDR4 SDRAM DDR5 SDRAM High Bandwidth Memory

HBM2 HBM3

Hybrid Memory Cube

Graphics

VRAM WRAM MDRAM SGRAM GDDR2 GDDR3 GDDR4 GDDR5 GDDR6

Rambus

RDRAM XDR DRAM XDR2 DRAM

Memory modules

SIMM DI

.