title: The maximum supported number of monitors in DirectX3D (D3D9)
body: <p>I'm developing the video wall system with Nvidia CUDA Decoder library for decoding and Directx3d(D3D9) for rendering. So, we assume that dozens of monitors can be installed in the system.</p>
  
  <p>(System: Intel I7 Processor, NVIDIA GTX 780 x 4EA, Windos 8 OS)</p>
  
  <p>But, IDirect3D9::GetAdapterCount API returns up to 12, even if more than 12 monitors are installed in the system. Namely, if there are 11 monitors in the system, the API returns 11. And if there are 12 monitors in the system, it returns 12. But, 13 monitors are installed in the system, the API returns 12, not 13.</p>
  
  <p>So, in that case, we cannot identify adapter ID of exceed monitors for rendering.
  As I know, Windows supports up 64 monitors. So I think that it is not a limitation of OS.</p>
  
  <p>I wonder if it is a limitation of D3D9. If you have some knowledge about it, please reply.</p>
  
  <p>Thank you.</p>