Northern Islands

The Northern Islands series is a family of GPUs developed by Advanced Micro Devices (AMD) for its Radeon line, based on the 40 nm process.

Starting with this family, the former ATI brand was officially discontinued in favor of making a correlation between the graphics products and the AMD branding for computing platforms (the CPUs and chipsets). Therefore, the AMD brand was used as the replacement. The logo for graphics products and technologies also received a minor makeover (using design elements of the 2010 AMD VISION logo).

Release

The original design was for 32 nm, but TSMC cancelled its 32 nm process in favor of 28 nm development. AMD was forced to adapt its designs as second generation 40 nm products. Even before canceling 32 nm process, TSMC priced their 32 nm process higher than 40 nm.^{[citation needed]} AMD calculated that for mid-range chips, the new VLIW4 architecture (at 32 nm), would not be as cost effective as an updated VLIW5 on 40 nm.^{[citation needed]}

Due to a major delay caused by the 32 nm cancellation, the top parts, Cayman and Antilles (dual Cayman), were delayed causing the mid-range part (Barts) of the series, as AMD moved the smaller chips (Barts, Turks, and Caicos) to 40 nm early, to be launched first.^[2] Also, AMD added stereoscopic 3D support to this Radeon lineup along with HDMI 1.4a and DisplayPort 1.2.

Products

Radeon HD 6400

Codenamed Caicos, this entry-level GPU was released along with Turks on February 7, 2011. The sole Caicos product is the Radeon HD 6450, meant to replace the HD 5450. Compared to the 5450, it has double the stream processors, GDDR5 support, along with new Northern Island technologies.

Radeon HD 6500/6600

Codenamed Turks, these entry-level GPUs were released on February 7, 2011. The Turks family includes Turks PRO and Turks XT which are marketed as HD 6570 and HD 6670 respectively. They were originally released to OEMs only, but later released to retail.

The Radeon HD 6570 and 6670 are minor upgrades of their Evergreen counterparts, the HD 5570 and 5670. Turks GPUs contain 80 more stream processors and 4 more texture units. They have also been upgraded to support the new technologies found in the Northern Islands GPUs such as HDMI 1.4a, UVD3, and stereoscopic 3D.

Radeon HD 6700

Codenamed Barts LE, the Radeon HD 6790 was released on April 5, 2011. There is one retail product available, the Radeon HD 6790. Barts uses shaders of the same 5-way VLIW architecture as HD 5000 series.

• HD 6790 has 800 stream processors at 840 MHz, a 256-bit memory interface and 1 GB GDDR5 DRAM at 1 GHz with maximum power draw of 150W. Performance is superior to the NVIDIA GTX 550 Ti and Radeon HD 5770, less powerful than the Radeon HD 6850 and close to the GTX 460 768MB and Radeon HD 5830.

AMD has confirmed that the HD 6700 cards use the Juniper XT and Juniper Pro cores from the HD 5700 series, and therefore they are not formally Northern Islands GPUs. Thus 6770 and 6750 are essentially the 5770 and 5750 respectively, with label being the main difference. There are a few enhancements to the 5700 series including:

• In the HD 6000-series cards, AMD’s Universal Video Decoder was upgraded to version 3.0 which supported Blu-ray 3D codecs, hardware decoding for DivX / XviD and a list of other improvements. The HD 6750 and HD 6770 adds the MVC decode capability of UVD 3.0, but not the rest of the UVD 3.0 features.^[3]

• According to AMD, these cards have been upgraded to support HDMI 1.4a but without the 3D features brought forward by UVD 3.0.

Radeon HD 6800

Codenamed Barts, the Radeon HD 6800 series was released on October 22, 2010. Products include Radeon HD 6850 and Radeon HD 6870. Barts uses shaders of the same 5-way VLIW architecture as HD 5000 series.^[4]

• HD 6850 has 960 stream processors at 775 MHz, a 256-bit memory interface and 1 GB GDDR5 DRAM at 1 GHz with maximum power draw of 127 W. Compared to competitors of the GTX 460 series, performance falls in line with the 1 GB cards of the NVIDIA GTX 460 series and superior to the 768MB GeForce GTX 460. Compared to predecessor graphics of the Radeon 5800 series, the 6850 is significantly faster than the Radeon HD 5830 and close to the performance of the Radeon HD 5850. A single 6-pin PCIe power connector requirement makes it suitable for most power supplies.

• HD 6870 has 1120 stream processors at 900 MHz( can be overclocked to 1100 MHz), a 256-bit memory interface and 1 GB GDDR5 DRAM at 1.05 GHz (can be overclocked to 1.2 GHz (4.2 GHz effective)) with a maximum power draw of 151 W. Performance is superior to the GeForce GTX 460, comparable to the GeForce GTX 560, and less than the GeForce GTX 560 Ti. HD 6870x2 with two Barts XT GPUs by Powercolor has 2GB GDDR5 DRAM, 256 x2 bit memory interface and needs twice the power (two 8 pin connectors from a 650 W PSU)more than a HD 6870 graphics card. Having computational power nearly 4.1 TFOLPS is available at stores priced at 500$+ with the same clock rates. Compared to predecessor graphics cards of the Radeon 5800 series, the 6870 is faster than the HD 5850 and close to the performance of the Radeon HD 5870.^[5]

Radeon HD 6900

This family includes three different high-end products.

Codenamed Cayman, the Radeon HD 6900 series was expected to be released on November 12, 2010. These release dates were pushed further back and Cayman was released on December 15, 2010. Products include Radeon HD 6950 and Radeon HD 6970. Cayman is based on new 4-way VLIW architecture, which was chosen over AMD's older VLIW5 in order to reduce complexity in the design of AMD's stream processors. Studies showed that few applications fully leveraged the extra stage in a VLIW5 SP. Reducing the stream processors to VLIW4 allows AMD to save on transistors for each individual SP and add more overall in the future.^[6]

• In games, the performance of HD 6970 is comparable to the NVIDIA GeForce GTX 570 and GTX 480. The Radeon HD 6950 is slightly slower than the 6970, comparable to slightly faster than the GTX 560 Ti and faster than the HD 5870. The HD 6950 was further discovered to be nearly identical to the 6970 in core design, though the 6950 has lower rated GDDR5 memory. Other than that, the two only differed in BIOS flashed software. As such, a BIOS flash would essentially upgrade the 6950 to a 6970. This was later addressed by AMD and its partners by laser cutting the extra cores (rather than simply disabling them in BIOS), and/or using non-reference card designs that would not work with a 6970 BIOS. Some 6950s can still be "unlocked", but it is much more difficult, requiring careful card selection and custom BIOS.

• Codenamed Antilles, the Enthusiast dual-GPU (dual-6970) Radeon HD 6990 was launched on March 9, 2011. It features an 830 MHz reference engine clock speed, 3072 stream processors, 5.1 TFLOPS computing performance, 192 texture units, 4 GB of GDDR5 frame buffer (DRAM), and 375 W maximum board power.^[7]

• The AMD Radeon HD 6990 (As with some other 6000 Series AMD Cards) comes with a dual BIOS switch. This enables what some claim to be a hidden 'AMD Uber Mode', however it is used most commonly as a backup when flashing the BIOS. (The same method used to flash the HD 6950 to appear as a HD 6970)^[8]

Brazos

AMD's Brazos APUs also use the Radeon HD 6000 model name but they do not use Northern Islands GPUs.

ASIC table

Northern Islands (HD 6xxx) series overview

• All models manufactured in a 40 nm fabrication process.
• All models support DirectX 11, OpenGL 4.1 and OpenCL 1.1

• ¹ Unified Shaders (Vertex shader/Geometry shader/Pixel shader) : Texture mapping unit : Render Output unit
• ² The effective data transfer rate of GDDR5 is quadruple its nominal clock, instead of double as with other DDR memory.
• ³ The TDP is reference design TDP values from AMD. Different non-reference board designs from vendors may lead to slight variations in actual TDP.

See also

• Radeon
• Evergreen (GPU family)
• Southern Islands (GPU family)

References

External links

• John Pearce (May 02, 2012). "AMD's Radeon HD 6970 Performance Comparsion". hardinfo-benchmark.com. http://www.hardinfo-benchmark.com/compare/Video-Card/16/amd-radeon-hd-6970-cayman-performance-review. Retrieved May 02, 2012. 
• David Kanter (December 14, 2010). "AMD's Cayman GPU Architecture". realworldtech.com. http://www.realworldtech.com/page.cfm?ArticleID=RWT121410213827. Retrieved January 10, 2011. 
• AMD Radeon HD 6000 series