updated 07:40 am EST, Wed December 15, 2010
AMD starts Radeon HD 6900 series with 6950, 6970
AMD on Thursday brought out the first high end Radeon HD 6000 chipsets in the 6950 and 6970. The two are the first to use the Cayman architecture that promises greater parallel processing with more instruction units and two full graphics engines working at the same time. They also ship with 2GB of RAM minimum, removing the frame buffer as a ceiling to performance at very high resolutions.
The two run at similar core clock speeds to their predecessors; the 6950 starts at 800MHz where the 6970 runs at 880MHz, comparing roughly to the 5870's 850MHz. They step down in stream (effects) processors from 1,600 to 1,408 and 1,536 respectively. However, both run at higher memory speeds (1.25GHz and 1.375GHz) and have more texture units, going from 80 on the 5870 to 88 on the 6950 and 96 on the 6970.
Both still have the hardware geometry tessellation, more natural morphological antialiasing and PowerTune optimization to both improve the performance and the power consumption when not running at peak speeds. A new antialiasing mode, Enhanced Quality, emulates NVIDIA's Coverage Sample mode and includes eight extra points where it determines the location of a polygon for sampling but without having to check the color. AMD envisions it as a near penalty-free way to improve antialiasing.
AMD unusually won't compare the performance in most areas to its own hardware, although tessellation speed is said to be about 2.9 times faster in the DirectX 11 and OpenGL games that support it. Most tests conducted at AnandTech showed the 6970 falling slightly short of the GeForce GTX 580 but the 6950 coming closer to the GTX 570.
AMD is primarily counting on a price advantage to beat NVIDIA. Boards are shipping today from third parties like MSI and PowerColor starting at $299 for the 6950 series and peaking at just $369 for the 6970, dropping well below the $349 and $499 official prices asked for the GeForce equivalents. Pre-built PCs should start arriving with the new cards in the near future.