AMD Cayman HD 6970 & HD 6950 Launch Review

AMD Radeon Graphics
The wait is over. Today AMD officially unwraps its highly anticipated new enthusiast class
graphics cards - the AMD Radeon HD 6900 series featuring the new ASIC codenamed
Cayman from the
Northern Island series, using a brand new architecture based on a four wide Very Large Instruction Width design (VLIW-4). Originally designated
Ibiza, and planned for TSMC's 32nm process node, AMD moved back to 40nm when
they determined that the cost benefit ratio simply didn't work - 32nm would be more expensive per transistor
than sticking with 40nm. With Evergreen, AMD had just released their first DirectX 11 graphics cards on 40nm, leaving few options for improving performance/watt and outright performance.
Still, this year's October launch of the AMD Radeon HD 6800 Barts series showed
AMD still had a few tricks up its sleeve, but those pale in comparison to what
we'll see today with Cayman.
 AMD Radeon HD 6970 |
 AMD Radeon HD 6950 |
Two Cayman cards are being introduced today - the AMD Radeon HD 6970 and the AMD Radeon HD 6950. The new VLIW-4 architecture means Stream Processor counts
are down, but they are fat little sausages compared to the ones inside the
Evergreen (HD 5000) and Bart (HD 6800) series Terascale 2 architecture. At AMD's
October technical press day in San Francisco, Rage3D heard how the Cayman architecture represents a risk for AMD
- a new architecture, a new approach. Below you can see how the new high end is positioned against the competition:
 AMD and NVIDIA Enthusiast Graphics Positioning |
Here's a brief overview of the product specifications:
AMD Radeon HD 6900 Cayman Specifications
 AMD Radeon HD 6900 - *denotes PowerTune default |

AMD
As usual, the
pre-launch rumor mill went wild with Cayman performance speculation. Performance bullshots and faked slide decks abounded, including an official-sounding email leaked detailing the delay of Cayman from the planned November 22nd launch until mid-December. In the meantime,
Nvidia delivered two mid-life kickers for the Fermi architecture, altering the
competitive landscape by pumping out the GeForce GTX 580 and GeForce GTX 570. Things
were getting ugly. How ugly, we're about to find out as we test Sapphire's HD 6970 and an AMD Radeon HD 6950,
then adding a second HD 6970 for some Crossfire action - all against the lean (well...) mean Fermi machines.