Graphics double data rate

Hynix 256 MBit GDDR-SDRAM

Gddr shortly GDDR , the additional term for DDR - RAM , which for graphics cards is designed.

Types

GDDR Gen.	I / O clock (GHz)	Transfer (GHz)	GB / s (32 bit)	GB / s (8 × 32 bit)	Bus width	pre- fetch	Operating voltage VDD / VDDQ	casing	JEDEC standard
1	0.16 ... 0.4	0.32 ... 0.8	1.3 ... 3.2	10.2 ... 25.6	2 ×32 bit	02-way	02.5V / 2.5V		JESD21C-2005, 3.11.5.2
2	00.4 ... 0.5	00.8 ... 1	3.2 ... 4	25.6 ... 32	2 ×32 bit		02.5V / 1.8V		JESD21C-2005, 3.11.5.6
3	00.7 ... 1.3	01.4 ... 2.6	5.6 ... 10	, 045… 83	2 ×32 bit	04-way	01.8V / 1.8V	170-ball FBGA	JESD21C-2005, 3.11.5.7
4th	0.00… 1.6	0.00... 3.2	0.0… 13	00.0... 102	2 ×32 bit	08-fold			JESD21C-2005, 3.11.5.8
5	01.8 ... 4	03.6 ... 8	,14 ... 32	,115 ... 256	2 ×32 bit	08-fold	01.5V / 1.5V	170-ball FBGA	JESD212C-2016
5X	0.05… 7	0,10 ... 14	,40 ... 56	,320 ... 448	2 ×32 bit	16-fold	1.35V / 1.35V	190-ball FBGA	JESD232A-2016
6th	03.5 ... 4.5	0,14 ... 18	,56… 72	,448 ... 576	2 × 16 bit	16-fold	1.35V / 1.35V	180-ball FBGA	JESD250A-2017

The following GDDR types have been developed so far:

(G) DDR

GDDR is based on memory modules according to the DDR-SDRAM standard. In this first generation, the voltage of VDD and VDDQ is 2.5 V. With clock rates from 166 to 400 MHz and read latencies of 3, 4 and 5 clock cycles, a maximum data throughput of 25.6 GB / s at 256 bits is achieved - Connection reached. GDDR works like the DDR-SDRAM with a double prefetch .

GDDR2

As a further development of GDDR, GDDR2 represented an unpopular intermediate step, although higher clock frequencies were achieved, GDDR2 had problems with the resulting waste heat at high frequencies. Only a few graphics cards such as the GeForce FX 5800 Ultra used GDDR2 with a maximum clock frequency of 500 MHz, most manufacturers use a maximum of 400 MHz or less. Features were the VDD / VDDQ voltages of 2.5 / 1.8 V, clock rates from 400 MHz to 500 MHz and read latencies of 5 to 7 clock cycles. This enabled a maximum data throughput of 32 GB / s with a 256-bit connection.

GDDR3

Two GDDR3 memory chips (center) on a graphics card

GDDR3 is based on DDR2 SDRAM . As with (G) DDR, the high memory rate was optimized by means of lower access times and changed read latencies. GDDR3 works like DDR2-SDRAM with a VDD / VDDQ voltage of 1.8 V. With clock rates from 700 to 1300 MHz and read latencies of 5 to 9 clock cycles, a maximum data throughput of 83.2 GB / s is at 256-bit Connection possible. Like the DDR2-SDRAM, GDDR3 works with a quadruple prefetch .

Although GDDR3 was designed by ATI , it was first used in March 2004 on the Nvidia Geforce FX 5700 Ultra and then on the Geforce 6800 Ultra . At ATI itself, the memory was installed for the first time in the Radeon X800 . Other well-known products in which GDDR3 is used are Sony's PlayStation 3 (256 MB for the graphics card) and Microsoft's Xbox 360 (512 MB are used by the CPU and GPU at the same time).

GDDR4

GDDR4 uses an eight- fold prefetch and is therefore based on a DDR3 -like technology. The doubling of the prefetch compared to GDDR3 allows higher transmission rates with a more moderate internal clock. As a result, the supply voltage could also be reduced. Series production of GDDR4 began at Samsung on July 5, 2006. Hynix offers GDDR4 chips with a clock frequency of up to 1.6 GHz. In combination with a 256-bit memory interface, a memory bandwidth of up to 102.4 GB / s can be achieved. The first use of GDDR4 memory on a graphics card was on the Radeon X1950 XTX from ATI, which was specified with a memory clock of 1 GHz. Another use of GDDR4 memory took place in the Radeon HD 3870 . However, GDDR4 was never able to establish itself on a broad front, probably also because GDDR3 achieved a clock frequency of more than 1 GHz thanks to manufacturing progress.

GDDR5

GDDR5 chips are available with a capacity of 512 Mbit to 8 Gbit. With clock frequencies between 1.8 and 4 GHz, transfer rates of 3.6 to 8 GT / s result. With × 32 chips this results in 14.4 to 32 GByte / s, with graphics processors with 256 data lines and 8x GDDR5 chips between 115.2 and 256 GByte / s. The first graphics card with GDDR5 was the ATI Radeon HD 4870 , which in the first versions had 512 MB of GDDR5 memory (3.6 GT / s and 115.2 GB / s). Mass production began in the first half of 2008. Qimonda shipped the first GDDR5 SDRAM chips in large numbers, while Hynix presented the first samples. Samsung has announced GDDR5 memory with a reduced supply voltage of 1.35 V. Sony uses 8 GByte GDDR5 with 176 GByte / s bandwidth as system memory for the PlayStation 4 . Samsung was the first to announce the mass production of 8 GBit GDDR5 memory chips.

GDDR5X

GDDR5X was presented in 2015 and introduced on May 27, 2016 with the Geforce GTX 1080 . At transfer rates of 10 to (planned) 14 Gbit / s per pin, between 320 and 448 GByte / s can be transferred via a 256-bit interface.

GDDR6

GDDR6 is being developed by the memory manufacturer Micron . As Golem reported on December 22, 2017, Micron has completed development and is distributing the first test samples to the hardware manufacturers. Series production has been running since 2018.

The GDDR6 memory modules use 180 pins instead of 190 pins for GDDR5 (X). They are also operated with a voltage of 1.35 V as with GDDR5X. The memory bandwidth is said to be 16 GBit / s, whereby the test patterns only achieve 14 GBit / s. Samsung and SK Hynix are also working on GDDR6 modules. The first widely available graphics cards with GDDR6 are the GeForce RTX cards from Nvidia released in September 2018.

Individual evidence

1. ↑ Specification at jedec.org ( Memento from September 26, 2007 in the Internet Archive ; PDF)
2. ↑ Data sheet for Samsung's 512Mbit-GDDR4-SGRAM (PDF)  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
3. ↑ Data sheet for the 512 Mbit GDDR4 SDRAM from Hynix ( Memento of the original from September 24, 2015 in the Internet Archive ; PDF) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
4. ↑ xbitlabs.com ( Memento of the original from April 2, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
5. ↑ wccftech.com
6. ↑ Hynix: GDDR5 memory for graphics chips from mid-2008. Heise online, accessed on February 8, 2008 . 
7. ↑ Specifications at qimonda.com (PDF)  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
8. ↑ Message about announcement. computerbase.de
9. ↑ Sony Computer Entertainment Inc. Introduces Playstation®4 ( Memento of the original from February 21, 2013 in the Internet Archive ; PDF; 386 kB) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. SCEI.co.jp, February 20, 2013 (English). Retrieved February 21, 2013. 
10. ↑ Samsung: Samsung Electronics Starts Mass Producing Industry's First 8-Gigabit Graphics DRAM (GDDR5). January 15, 2015, accessed February 9, 2015 . 
11. ↑ Micron's GDDR6 for graphics cards is ready. Golem, December 22, 2017, accessed January 29, 2018 . 
12. ↑ Series production of GDDR6 is coordinated with partners . In: Golem.de . September 29, 2018 ( golem.de [accessed February 4, 2019]).