Microsoft Corp., the world’s largest maker of software, will not release next-generation graphics application programming interface (API) called DirectX 10 for the currently shipping Windows XP operating system (OS), instead, the company will keep the new API strictly for the forthcoming Windows Vista OS, despite earlier assumptions about DirectX 10 for the XP.

During a DirectX 10-related event in London, UK, Richard Huddy, ATI Technologies’ software developers relations chief, said that Microsoft’s Vista will integrate DirectX 10 and DirectX 9 APIs for different types of hardware, but the current Windows XP will not get DirectX 10 support, as suggested some rumours earlier. For end users this means that to get the most advantages of the new-generation graphics processing units (GPUs), the new OS will be required.

Both ATI Technologies and Nvidia Corp. planned to release hardware that supports DirectX 10 capabilities as early as in the second half 2006, however, if there will be no API, which unveils the features of the hardware, the companies may reconsider their plans.

Microsoft Windows Vista is expected to be available in very early 2007.

DirectX 10 API, which is also referred to as Windows Graphics Foundation 2.0, solves numerous performance-related problems, particularly, it shrinks overhead time spent by API and driver on execution. Additionally, ATI says its first DirectX 10 graphics processor – code-named R600 – will have unified shader micro-architecture, which will allow to boost performance even further compared to currently existing micro-architectures and . The performance improvements are conditioned by a special built-in arbiter processor, which will “tailor” rendering of every frame across the 64 unified shader pipelines. Such an approach, according to ATI, allows to utilize all execution engines within the chip, while in traditional architectures – where pixel shaders and vertex shaders are calculated by dedicated units – some of the arithmetic processors may stand idle waiting for others to complete their tasks.

Microsoft Corp., who develops DirectX API collaboratively with companies like ATI and Nvidia, did not comment on the news-story.