DirectX 10 what's new???

Microsoft DirectX is a set of APIs for handling tasks related to multimedia, and gaming. It was designed to provide a much broader gaming or multimedia environment. Starting off with DirectX 3, various DirectX versions are out, namely DirectX 3, 5, 6, 7, 8 and 9. It works by giving direct access to low-level functions of a peripheral by providing a set of APIs (application programming interface).Every new version of DirectX adds support for new hardware features, allowing game developers to push the boundaries of realism a little bit further.
DirectX9 being a huge hit embedded a lot of unique and new features but due to fixed number of vertex units and pixel processing units and its huge dependability on CPU DirectX9 had to face problems like API object overhead.
With games becoming more and more realistic there was need for a newer and powerful API, and the answer came as DirectX 10.The API of DirectX 10 has been written from ground and the new and improved API reduces API overhead to a greater extent. Object overhead is also reduced so that more unique objects can be shown in a scene at one time. A new exciting feature called Geometry shader is added in the new API. So, what makes DirectX10 so powerful? The answer lies in the unified architecture of the new API. This unified API and GPU architecture sums the traditional vertex, pixel and geometry units into one processing units instead of separate ones. So the API can handle these instructions through one single instruction only. The key idea behind a unified architecture is to make the GPU from a render processor to a complete processor; i.e the GPU can now perform more functions like physics, AI, animation and many other processes improving the gaming experience. New features will also allow the possibility of new 3D effects in games.
Although power packed the only demerit with DirectX10 is that it is tied to Windows Vista, so in need to experience DirectX10 powered games we have to switch to windows vista. For now, the DirectX 10 API is a move in the right direction when it comes to gaming, and it can be easily said that it will allow future GPUs from ATI and NVIDIA to rise in the gaming arena.
The figure shows how images are rendered in DirectX10: