GDDR3
Encyclopedia
Graphics Double Data Rate 3 is a graphics card-specific memory technology, designed by ATI Technologies
with the collaboration of JEDEC
.
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. GDDR3 is not related to the JEDEC
DDR3 specification. This memory uses internal terminators, enabling it to better handle certain graphics demands. To improve throughput, GDDR3 memory transfers 4 bit
s of data per pin in 2 clock cycles.
The GDDR3 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 strobe
s are organized per byte of the 32 bit wide interface.
, the first card to use the technology was nVidia
's GeForce FX
5700 Ultra, where it replaced the GDDR2 chips used up to that time. The next card to use GDDR3 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. GDDR3 was 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
's Xbox 360
is shipped with 512 MB of GDDR3 memory, and is helping to pioneer the use of this memory as standard system memory rather than only video memory. Nintendo
's Wii
also contains 64 MB of GDDR3 memory.
ATI Technologies
ATI Technologies Inc. was a semiconductor technology corporation based in Markham, Ontario, Canada, that specialized in the development of graphics processing units and chipsets. Founded in 1985 as Array Technologies Inc., the company was listed publicly in 1993 and was acquired by Advanced Micro...
with the collaboration of JEDEC
JEDEC
The JEDEC Solid State Technology Association, formerly known as the Joint Electron Devices Engineering Council , is an independent semiconductor engineering trade organization and standardization body...
.
It has much the same technological base as DDR2
DDR2 SDRAM
DDR2 SDRAM is a double data rate synchronous dynamic random-access memory interface. It supersedes the original DDR SDRAM specification and has itself been superseded by DDR3 SDRAM...
, but the power and heat dispersal requirements have been reduced somewhat, allowing for higher performance memory modules, and simplified cooling systems. GDDR3 is not related to the JEDEC
JEDEC
The JEDEC Solid State Technology Association, formerly known as the Joint Electron Devices Engineering Council , is an independent semiconductor engineering trade organization and standardization body...
DDR3 specification. This memory uses internal terminators, enabling it to better handle certain graphics demands. To improve throughput, GDDR3 memory transfers 4 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s of data per pin in 2 clock cycles.
The GDDR3 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 strobe
Data strobe encoding
Data strobe encoding is an encoding scheme for transmitting data in digital circuits.It uses two signal lines , Data and Strobe...
s are organized per byte of the 32 bit wide interface.
Commercial implementation
Despite being designed by ATIATI Technologies
ATI Technologies Inc. was a semiconductor technology corporation based in Markham, Ontario, Canada, that specialized in the development of graphics processing units and chipsets. Founded in 1985 as Array Technologies Inc., the company was listed publicly in 1993 and was acquired by Advanced Micro...
, the first card to use the technology was nVidia
NVIDIA
Nvidia is an American global technology company based in Santa Clara, California. Nvidia is best known for its graphics processors . Nvidia and chief rival AMD Graphics Techonologies have dominated the high performance GPU market, pushing other manufacturers to smaller, niche roles...
's GeForce FX
GeForce FX
The GeForce FX or "GeForce 5" series is a line of graphics processing units from the manufacturer NVIDIA.-Overview:...
5700 Ultra, where it replaced the GDDR2 chips used up to that time. The next card to use GDDR3 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
GeForce FX
The GeForce FX or "GeForce 5" series is a line of graphics processing units from the manufacturer NVIDIA.-Overview:...
. ATI began using the memory on its Radeon X800
Radeon R420
The Radeon R420 core from ATI Technologies was the company's basis for its 3rd-generation DirectX 9.0/OpenGL 2.0-capable graphics cards. Used first on the Radeon X800, R420 was produced on a 0.13 micrometer low-K process and used GDDR-3 memory...
cards. GDDR3 was Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
's choice for the PlayStation 3
PlayStation 3
The is the third home video game console produced by Sony Computer Entertainment and the successor to the PlayStation 2 as part of the PlayStation series. The PlayStation 3 competes with Microsoft's Xbox 360 and Nintendo's Wii as part of the seventh generation of video game consoles...
gaming console's graphics memory, although its nVidia
NVIDIA
Nvidia is an American global technology company based in Santa Clara, California. Nvidia is best known for its graphics processors . Nvidia and chief rival AMD Graphics Techonologies have dominated the high performance GPU market, pushing other manufacturers to smaller, niche roles...
based GPU is also capable of accessing the main system memory, which consists of XDR DRAM
XDR DRAM
XDR DRAM or extreme data rate dynamic random access memory is a high-performance RAM interface and successor to the Rambus RDRAM it is based on, competing with the rival DDR2 SDRAM and GDDR4 technology. XDR was designed to be effective in small, high-bandwidth consumer systems, high-performance...
designed by Rambus Incorporated (Similar technology is marketed by nVidia as TurboCache in PC platform GPUs). Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's Xbox 360
Xbox 360
The Xbox 360 is the second video game console produced by Microsoft and the successor to the Xbox. The Xbox 360 competes with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generation of video game consoles...
is shipped with 512 MB of GDDR3 memory, and is helping to pioneer the use of this memory as standard system memory rather than only video memory. Nintendo
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
's Wii
Wii
The Wii is a home video game console released by Nintendo on November 19, 2006. As a seventh-generation console, the Wii primarily competes with Microsoft's Xbox 360 and Sony's PlayStation 3. Nintendo states that its console targets a broader demographic than that of the two others...
also contains 64 MB of GDDR3 memory.
Advantages of GDDR3 over DDR2
- GDDR3s strobe signal unlike DDR2 SDRAMDDR2 SDRAMDDR2 SDRAM is a double data rate synchronous dynamic random-access memory interface. It supersedes the original DDR SDRAM specification and has itself been superseded by DDR3 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.
- GDDR3 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 throughputThroughputIn communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node...
and more precise timings.