I just converted my Direct3D application from version 8.1 to version 9.0. Before conversion, when running at 1024x768 (windowed), I was getting approximately 116 FPS. After converting to DirectX 9.0, my frame rate dropped sharply to 47 FPS. When running full-screen, however, I max out at 85 FPS, which is my monitor''s refresh rate. If I increase resolution to 1600x1200 (full-screen), both D3D8 and D3D9 give me around 45 FPS, so apparently, the performance drop is only affecting windowed mode. I even tried running my program in a window with an empty scene (no object being drawn) and I get similar results (217 FPS for 8.1 and 50 FPS for 9.0). And that''s with an empty scene!!! So my question is: does DirectX 9 have problems with windowed mode? Has something changed that I need to modify in my code in order to get similar performance between D3D8 and D3D9? Thanks for any advice!

You should read over the changes in DX9 (it''s in the docs).

Try setting your presentation interval to IMMEDIATE in windowed mode.

Thanks a lot guys! That did the trick, although I still get between 6 to 10 FPS less than with D3D8, but that''s not as big a deal.