Radeon HD 6000 series

The Northern Islands series is a family of GPUs developed by Advanced Micro Devices (AMD) forming part of its Radeon-brand, based on the 40 nm process. Some models are based on TeraScale 2 (VLIW5), some on the new TeraScale 3 (VLIW4) introduced with them.
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). This also marks the end of the "Mobility Radeon" name in their laptop GPUs, keeping only the "M" suffix in the GPU model number to signify a Mobile variant.
Its direct competitor was Nvidia's GeForce 500 Series; they were launched approximately a month apart.
Architecture.
This article is about all products under the Radeon HD 6000 Series brand.
Multi-monitor support.
The AMD Eyefinity-branded on-die display controllers were introduced in September 2009 in the Radeon HD 5000 Series and have been present in all products since.
Video acceleration.
Unified Video Decoder (UVD3) is present on the die of all products and supported by AMD Catalyst and by the free and open-source graphics device driver.
OpenCL (API).
OpenCL accelerates many scientific Software Packages against CPU up to factor 10 or 100 and more.
Open CL 1.0 to 1.2 are supported for all Chips with Terascale 2 and 3.
Products.
The 6800 series was the first batch of the Radeon 6000 series. Codenamed "Northern Islands", this series was released on October 22, 2010 after brief delays. Over the following months, the budget, midrange, and high-end cards were filled into the series.
Radeon HD 6400.
AMD released the entry-level Radeon HD 6400 GPU on February 7, 2011. Codenamed "Caicos", it came to market at the same time as the Radeon HD 6500/6600 "Turks" GPUs. The sole Caicos product, the Radeon HD 6450, aimed 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.
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:
Radeon HD 6800.
Codenamed "Barts", the Radeon HD 6800 series was released on October 23, 2010. Products include Radeon HD 6850 and Radeon HD 6870. Barts uses shaders of the same 5-way VLIW architecture as HD 5000 series.
Radeon HD 6900.
This family includes three different high-end products all based on TeraScale 3 (VLIW4)
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.
AMD PowerTune was introduced with Radeon HD 6900 series.