FSX is short for Flight Simulator X, a game developed by Microsoft for Windows that allows you to simulate flying an aircraft. DirectX enhances the performance of your PC when you play video games and movies that require a lot of use of your video graphics card. DirectX 10 is the latest version of this technology. DirectX creates extra audio and video effects that come with video games and other multimedia. You can download DirectX 10 for FSX; however, you must enable it in the game.
Download and install the FSX service pack in the "Resources" section. The service pack includes DirectX 10.
Launch FSX. Double-click the "FSX" icon on your desktop.
Click "Options > Settings" and then click "Display."
Click the tab that says, "Graphics" and then add a checkmark to the box, "DirectX 10 preview."
Click "OK" to enable DirectX 10. You now have DirectX 10 for FSX.