Following recent reports that Nvidia's Kepler GPUs do nt fully support DirectX 11.1, AMD followed up claiming that its latest Radeon cards should be the users's choice for Windows 8 systems.

Windows 8 brings DirectX 11.1, which delivers improvements in a variety of areas, including stereo 3D support, video processing, GPU compute, 2D rendering, and even power efficiency. AMD claims that it has embraced all of the changes and made them a part of its GCN Architecture well ahead of the commercial release of Microsoft Windows 8.

DirectX 11.1 is intended to support a wide range of different GPU architectures with different capabilities. According to reports, Nvidia has recently said that the Kepler architecture does not include all aspects of DirectX 11.1. However, David Nalasco, the Senior Technical Marketing Manager, Product Group at AMD, claims that Nvidia did not support 4 of the 10 key technologies comprising Feature Level 11_1.

While every new version of DirectX adds support for new features, it also has to maintain support for older, less capable hardware. Since the release of DirectX 11, this has been managed using "feature level" terminology. A feature level determines a particular set of features from a given DirectX version that a GPU design can support. If the feature level of a GPU matches the DirectX version it supports, that generally means all of the features of that version are available, while lower feature levels indicate only a subset of the features are exposed.

As an example of how feature levels can add confusion, DirectX 11.1 comprises Feature Level 11_0 and Feature Level 11_1. This means that even though a GPU claims to support DirectX 11.1, it may in fact only support Feature Level 11_0, or, as in the case of Nvidia's Kepler GPUs, only partially support Feature Level 11_1.

Mr.Nalasco claims that AMD's Graphics Core Next (GCN) Architecture, available in AMD Radeon HD 7700, HD 7800 and HD 7900 Series graphics, along with AMD FirePro W series cards, provide complete support for DirectX 11.1 Feature Level 11_1 in Windows 8.

"Well, for one, AMD fully supports DirectX 11.1, whereas currently Nvidia does not, so if you're planning to install Windows 8, or buying a new system that already has it installed, then we recommend you make sure your system includes an GCN-based AMD Radeon HD 7000-series graphics card or AMD FirePro W series card," Nalasco wrote on a blog post. "This will not only ensure you're getting the most out of the new operating system today, but also maximize the usefulness of your graphics purchase down the road."