The new PowerTune feature of the Radeon HD 6900 cards sort of works like that, but in reverse: The core clock speed is set very high, and if the chip starts to run too hot, PowerTune lowers the clock speed in small steps until it’s back at a safe level.

PowerTune technology: CPUs from Intel and AMD have a “turbo” feature that can crank up the clock speed a bit if the chip happens to be running beneath its rated thermal threshold. (Tessellation is a DirectX 11 feature that breaks up large polygons into lots of smaller polygons, to add detail or to smooth the edges of 3D models.) Here’s a breakdown of some of the new features in the Cayman GPU found on the Radeon HD 6900 cards. This design should dramatically improve performance in geometry-intensive applications, particularly those that have a lot of tessellation. The chip features two “front-end” graphics engines, with two thread dispatch processors, two geometry tessellation units, and two vertex processing engines. The architecture of the Cayman GPU is fairly new, with quite a few changes from that of the Radeon HD 5000 series and Radeon HD 6800 series. Nevertheless, they offer good power efficiency for their class, as well as lots of other interesting features. Both the Radeon HD 6970 and the Radeon HD 6950 are quite long, too, and won’t fit in smaller PCs (as is often the case with high-end enthusiast cards). Anyone hoping that AMD would reclaim the absolute speed crown from Nvidia will be disappointed. The Radeon HD 6900 series cards are certainly fast, though the 6970 doesn’t always fare better than the Nvidia GeForce GTX 570 against which it is priced to compete.

AMD has redesigned the shader units for improved efficiency, greatly enhanced geometry performance, and employed a whole new power-management system. Code-named Cayman, this new GPU doesn’t merely take the architecture of the Radeon HD 6800 series and scale it up rather, it makes significant architectural changes. Instead of its usual tactic of addressing the higher end of the market with a graphics card containing two of the GPUs powering the Radeon HD 6870 (a chip code-named Barts), it is using a single, larger, more-powerful new GPU. AMD is trying something new with its Radeon HD 6900 series of graphics cards.

Amd radeon hd 6700 series specs