Windows 7 comes with a new version of DirectX, a graphics and sound standard which delivers better image quality, eye-popping 3D visuals, immersive sound effects and improved performance vital to many of today's PC games.
This version of DirectX is refined to leverage the power of multi-core processors to deliver sophisticated shading and texturing techniques such as tessellation, more efficient Anti-Aliasing and Vsync, smoother 3D lifelike graphics and nuanced sound.
You can check the version of DirectX on your system by Opening the DirectX Diagnostic Tool. Just Open the Run Command Dialog box by pressing Win+R and entering dxDiag. In it, check the System Information in System tab for the DirectX version number.