GDDR5 (Graphics Double Data Rate, version 5) is a type of graphics card memory. It conforms to the standards which were set out in the GDDR5 specification by the JEDEC. GDDR5 is the successor to GDDR4. Unlike its predecessors, it has two parallel DQ links which provide doubled I/O throughput when compared to GDDR4. GDDR5 SGRAM is a high performance dynamic random-access memory designed for applications requiring high bandwidth. GDDR5 SGRAM uses a 8n prefetch architecture and DDR interface to achieve high performance operation and can be configured to operate in x32 mode or x16 (clamshell) mode which is detected during device initialization. The GDDR5 interface transfers two 32 bit wide data words per WCK clock cycle to/from the I/O pins. Corresponding to the 8n prefetch, a single write or read access consists of a 256 bit wide two CK clock cycle data transfer at the internal memory core and eight corresponding 32 bit wide one-half WCK clock cycle data transfers at the I/O pins.
Qimonda, a spin-off of Infineon, has demonstrated and sampled GDDR5 [1], and released a paper about the technologies behind GDDR5 [2]. On May 10, 2008, Qimonda announced volume production of 512 Mib GDDR5 modules rated at 3.6 Gbit/s (900 MHz), 4.0 Gbit/s (1 GHz), and 4.5 Gbit/s (1.125 GHz).[3].
Samsung had announced plans for the transition to GDDR5 by the beginning of 2008 [4]. It had since announced that it had developed GDDR5 memory at 6.0 Gbit/s at 512 Mib density.[5] On February 17, 2009, Samsung announced a 7Gbit/s 1Gb density part, allowing up to 28.2 GByte/sec bandwidth.[6]
Hynix Semiconductor has introduced the industry's first 1 Gib GDDR5 memory. It supports a bandwidth of 20 GB/s on a 32-bit bus, which enables memory configurations of 1 GiB at 160 GB/s with only 8 circuits on a 256-bit bus.[7]
On June 25, 2008, AMD became the first company to ship products using GDDR5 memory with its Radeon HD 4870 video card series, incorporating Qimonda's 512 Mb memory modules at 3.6 Gbit/s bandwidth.[8][9]
See also
References
- ^ Register report, retrieved November 2, 2007
- ^ Qimonda GDDR5 White PaperPDF (814 KiB)
- ^ GDDR5 in Production, New Round of Graphics Cards War Imminent., retrieved May 11, 2008
- ^ Electronic Design report, retrieved November 2, 2007
- ^ Samsung Announcement December 1, 2007.
- ^ http://www.dailytech.com/Samsungs+7Gbs+GDDR5+in+50nm+Mass+Production+Targets+40nm+GPUs/article14289.htm
- ^ "Hynix Introduces Industry's First 1 Gb GDDR5 DRAM". Hynix Semiconductor. 2007-11-15. http://www.hynix.com/allnews/eng/preng_readB.jsp?NEWS_DATE=2007-11-15:08:38:00. Retrieved 2007-11-19.
- ^ Qimonda Press Release. May 21, 2008
- ^ AMD Press Release. June 25, 2008
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