This is a DirectX 9 Graphics Client/Engine for free Orbiter SpaceFlight Simulator. It provides basically the same features as the Orbiter built-in engine, but using DirectX 9 interface instead. That will improve performance and framerate expecially on Windows 7 and 8 Systems
D3D9Client support thread is located in Orbiter Forum
. You may find some answers to your questions from there by searching the thread.
D3D9 improves framerates on XP Systems as well!Orbiter Beta
Download D3D9Client for orbiter beta from a download tab above