This article is about DDR graphics RAM (SGRAM). For non-graphics (dynamic) DDR memory, see DDR4 SDRAM.
GDDR4 SDRAM, an abbreviation for Graphics Double Data Rate 4 Synchronous Dynamic Random-Access Memory, is a type of graphics cardmemory (SGRAM) specified by the JEDEC Semiconductor Memory Standard.[1][2] It is a rival medium to Rambus'sXDR DRAM. GDDR4 is based on DDR3 SDRAM technology and was intended to replace the DDR2-based GDDR3, but it ended up being replaced by GDDR5 within a year.
On October 26, 2005, Samsung announced that it developed the first GDDR4 memory, a 256-Mbit chip running at 2.5 Gbit/s. Samsung also revealed plans to sample and mass-produce GDDR4 SDRAM rated at 2.8 Gbit/s per pin.[3]
In 2005, Hynix developed the first 512-Mbit GDDR4 memory chip.[4]
On February 14, 2006, Samsung announced the development of 32-bit 512-Mbit GDDR4 SDRAM capable of transferring 3.2 Gbit/s per pin, or 12.8 GB/s for the module.[5]
On July 5, 2006, Samsung announced the mass-production of 32-bit 512-Mbit GDDR4 SDRAM rated at 2.4 Gbit/s per pin, or 9.6 GB/s for the module. Although designed to match the performance of XDR DRAM on high-pin-count memory, it would not be able to match XDR performance on low-pin-count designs.[6]
On February 9, 2007, Samsung announced mass-production of 32-bit 512-Mbit GDDR4 SDRAM, rated at 2.8 Gbit/s per pin, or 11.2 GB/s per module. This module was used for some AMD cards.[7]
On February 23, 2007, Samsung announced 32-bit 512-Mbit GDDR4 SDRAM rated at 4.0 Gbit/s per pin or 16 GB/s for the module and expects the memory to appear on commercially available graphics cards by the end of year 2007.[8]
Technologiesedit
GDDR4 SDRAM introduced DBI (Data Bus Inversion) and Multi-Preamble to reduce data transmission delay. Prefetch was increased from 4 to 8 bits. The maximum number of memory banks for GDDR4 has been increased to 8. To achieve the same bandwidth as GDDR3 SDRAM, the GDDR4 core runs at half the performance of a GDDR3 core of the same raw bandwidth. Core voltage was decreased to 1.5 V.
Data Bus Inversion adds an additional active-low DBI# pin to the address/command bus and each byte of data. If there are at more than four 0 bits in the data byte, the byte is inverted and the DBI# signal transmitted low. In this way, the number of 0 bits across all nine pins is limited to four.[9]: 9 This reduces power consumption and ground bounce.
On the signaling front, GDDR4 expands the chip I/O buffer to 8 bits per two cycles, allowing for greater sustained bandwidth during burst transmission, but at the expense of significantly increased CAS latency (CL), determined mainly by the double reduced count of the address/command pins and half-clocked DRAM cells, compared to GDDR3. The number of addressing pins was reduced to half that of the GDDR3 core, and were used for power and ground, which also increases latency. Another advantage of GDDR4 is power efficiency: running at 2.4 Gbit/s, it uses 45% less power when compared to GDDR3 chips running at 2.0 Gbit/s.
In Samsung's GDDR4 SDRAM datasheet, it was referred as 'GDDR4 SGRAM', or 'Graphics Double Data Rate version 4 Synchronous Graphics RAM'. However, the essential block write feature is not available, so it is not classified as SGRAM.
Adoptionedit
The video memory manufacturer Qimonda (formerly Infineon Memory Products division) has stated it will "skip" the development of GDDR4, and move directly to GDDR5.[10]
^Choi, J.S. (2011). DDR4 Mini Workshop(PDF). Server Memory Forum 2011. This presentation is about DDR4 rather than GDDR4, but both use data bus inversion.
Samsung Mass Producing Most Advanced Graphics Memory: GDDR4, press release
April 12, 2024
gddr4, sdram, this, article, about, graphics, sgram, graphics, dynamic, memory, ddr4, sdram, abbreviation, graphics, double, data, rate, synchronous, dynamic, random, access, memory, type, graphics, card, memory, sgram, specified, jedec, semiconductor, memory,. This article is about DDR graphics RAM SGRAM For non graphics dynamic DDR memory see DDR4 SDRAM GDDR4 SDRAM an abbreviation for Graphics Double Data Rate 4 Synchronous Dynamic Random Access Memory is a type of graphics card memory SGRAM specified by the JEDEC Semiconductor Memory Standard 1 2 It is a rival medium to Rambus s XDR DRAM GDDR4 is based on DDR3 SDRAM technology and was intended to replace the DDR2 based GDDR3 but it ended up being replaced by GDDR5 within a year GDDR4 SDRAMGraphics Double Data Rate 4 Synchronous Dynamic Random Access MemoryType of RAMDeveloperJEDECTypeSynchronous dynamic random access memoryGeneration4th generationPredecessorGDDR3 SDRAMSuccessorGDDR5 SDRAM Contents 1 History 2 Technologies 3 Adoption 4 See also 5 References 6 External linksHistory editOn October 26 2005 Samsung announced that it developed the first GDDR4 memory a 256 Mbit chip running at 2 5 Gbit s Samsung also revealed plans to sample and mass produce GDDR4 SDRAM rated at 2 8 Gbit s per pin 3 In 2005 Hynix developed the first 512 Mbit GDDR4 memory chip 4 On February 14 2006 Samsung announced the development of 32 bit 512 Mbit GDDR4 SDRAM capable of transferring 3 2 Gbit s per pin or 12 8 GB s for the module 5 On July 5 2006 Samsung announced the mass production of 32 bit 512 Mbit GDDR4 SDRAM rated at 2 4 Gbit s per pin or 9 6 GB s for the module Although designed to match the performance of XDR DRAM on high pin count memory it would not be able to match XDR performance on low pin count designs 6 On February 9 2007 Samsung announced mass production of 32 bit 512 Mbit GDDR4 SDRAM rated at 2 8 Gbit s per pin or 11 2 GB s per module This module was used for some AMD cards 7 On February 23 2007 Samsung announced 32 bit 512 Mbit GDDR4 SDRAM rated at 4 0 Gbit s per pin or 16 GB s for the module and expects the memory to appear on commercially available graphics cards by the end of year 2007 8 Technologies editGDDR4 SDRAM introduced DBI Data Bus Inversion and Multi Preamble to reduce data transmission delay Prefetch was increased from 4 to 8 bits The maximum number of memory banks for GDDR4 has been increased to 8 To achieve the same bandwidth as GDDR3 SDRAM the GDDR4 core runs at half the performance of a GDDR3 core of the same raw bandwidth Core voltage was decreased to 1 5 V Data Bus Inversion adds an additional active low DBI pin to the address command bus and each byte of data If there are at more than four 0 bits in the data byte the byte is inverted and the DBI signal transmitted low In this way the number of 0 bits across all nine pins is limited to four 9 9 This reduces power consumption and ground bounce On the signaling front GDDR4 expands the chip I O buffer to 8 bits per two cycles allowing for greater sustained bandwidth during burst transmission but at the expense of significantly increased CAS latency CL determined mainly by the double reduced count of the address command pins and half clocked DRAM cells compared to GDDR3 The number of addressing pins was reduced to half that of the GDDR3 core and were used for power and ground which also increases latency Another advantage of GDDR4 is power efficiency running at 2 4 Gbit s it uses 45 less power when compared to GDDR3 chips running at 2 0 Gbit s In Samsung s GDDR4 SDRAM datasheet it was referred as GDDR4 SGRAM or Graphics Double Data Rate version 4 Synchronous Graphics RAM However the essential block write feature is not available so it is not classified as SGRAM Adoption editThe video memory manufacturer Qimonda formerly Infineon Memory Products division has stated it will skip the development of GDDR4 and move directly to GDDR5 10 See also editList of interface bit ratesReferences edit Standards amp Documents Search sgram www jedec org Retrieved 9 September 2013 Standards amp Documents Search gddr4 www jedec org Retrieved 9 September 2013 Samsung Electronics Develops Industry s First Ultra Fast GDDR4 Graphics DRAM Samsung Semiconductor Samsung October 26 2005 Retrieved 8 July 2019 History 2000s SK Hynix Retrieved 8 July 2019 Samsung Develops Ultra fast Graphics Memory A More Advanced GDDR4 at Higher Density Samsung sends GDDR4 graphics memory into mass production Samsung releases fastest GDDR 4 SGRAM The Inquirer Archived from the original on 2007 02 12 a href Template Cite web html title Template Cite web cite web a CS1 maint unfit URL link Samsung accelerates graphics memory to 2000 MHz Choi J S 2011 DDR4 Mini Workshop PDF Server Memory Forum 2011 This presentation is about DDR4 rather than GDDR4 but both use data bus inversion Softpedia reportExternal links editX Bit Labs GDDR4 closing in X Bit Labs GDDR4 achieving 3 2 GHz DailyTech ATI X1950 Now September 14 DailyTech ATI Radeon X1950 Announced Samsung Shipping Production GDDR4 Samsung Mass Producing Most Advanced Graphics Memory GDDR4 press release Retrieved from https en wikipedia org w index php title GDDR4 SDRAM amp oldid 1164837697, wikipedia, wiki, book, books, library,
