The ATI Radeon HD 3800 Series

The new ATI Radeon HD 3800 series of graphics cards is built around the ATI RV670 GPU. This new GPU is based on the same R600 architecture used in the Radeon HD 2900 XT, but with pretty significant improvements. Not only is it leaner in the number of transistors, it is the first graphics chip built on the smaller 55nm process technology. The result is a much smaller and cooler GPU than the R600.

This is also the first graphics chip in the world to support DirectX 10.1. Right now, the RV670's support for DirectX 10.1 is about as useful as its support for tessellation. Both are unlikely to be of any real value in the immediate future. As far as future-proofing is concerned, a new series of graphics cards will emerge from the ATI and NVIDIA factories before either feature becomes a real factor.

ATI decided to adopt AMD's new processor naming scheme to reduce confusion and streamline their products. It does away with the postfixes like XT, Pro, GT which can mean anything and often mean different things for ATI and NVIDIA. Although NVIDIA has publicly derided the new naming scheme, we do think it is a better system (for now). It certainly results in a slightly shorter name, which is always a good thing.

The ATI RV670 GPU

The RV670 is essentially an improved version of the R600 GPU. It has the same number of stream processors, texture units and ROPs, with support for DirectX 10.1 added. As the RV prefix denotes though, this is a value part, unlike the R600. As such, ATI cut down the 512-bit memory bus in the R600 to just 256-bit in the RV670. This gives the two Radeon HD 3800 series cards less memory bandwidth than the Radeon HD 2900 XT even with much higher memory clock speeds.

Even with the narrower memory bus, ATI claims the RV670 delivers the same performance as the Radeon HD 2900 XT (R600) on a clock-to-clock basis. To be honest, that claim is hardly impressive since the R600 was not a remarkable performer by the time it was released. However, with a higher clock speed, the RV670 will actually be faster than R600 and best of all, do it at a much lower cost.