title: DirectX 11 Swap Chain with 7 back buffers
body: <p>I have a propietary media player that runs on Windows 8 in desktop mode. Runtime DirectX version is 11, but native graphics driver support is for DirectX 9.<br>
  On some computers with the exact same setup, I see that the actual swap chain's back buffers count is 2, and the performance is great, and on some others the back buffer count is 7 and there are frames dropped.<br>
  I don't have the source code of that player and wonder what could be the reason for determining the different back buffer count number in runtime.<br>
    Can someone please explain why such backbuffer count leads to such change in performance? Or just point me to relevant documentation that explains the implications of backbuffers number?  </p>
  
  <p>(More debugging info: Using GPUView I see that when backbuffer count is 2 the hardware works in a synchronized mode, i.e. one packet in the HW queue in each second VSync (Clip frame rate is 30fps), when for the 7 backbuffers the work is done for 5-7 frames together, then some empty VSyncs, then 5-7 frames again and so on).  </p>
  
  <p>Thank you in advance!</p>