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Window mode faster than fullscreen?

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How can it be that my d3d app runs faster (higher fps) in window mode than in fullscreen? (40-50 FPS in windowmode and 30-40 FPS in fullscreen) And it''s not the vertical sync that does the difference. /lazy

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Are you sure that the render target has the same dimensions?

This could happen sometimes I think, but in most (normally in all ) cases fullscreen is much faster then windowed mode

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Yepp, the window is the same size as the fullscreen mode.

d3d is optimized for window apps???
Can''t be many games that run in window mode...
why would microsoft optimize for window mode more than
fullscreen apps??

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Original post by Lazy303

I use 32 bit color in both cases...
and it''s not the vertical sync since my fps is not
even near my monitors 75hz

But did you explicitly specify 75Hz in your presentation parameters when you created your D3D device?

If not, then the driver "default" fullscreen refresh rate will be used - which is most commonly 60Hz. If your app is running in a little less than a single frame, then for 60Hz refresh rates, the next multiple is 30Hz (i.e. 30fps). For your 75Hz desktop refresh rate that''s 37.5.

Other thoughts:
- As Lupin asked, are the dimensions of the surface exactly the same for windowed and fullscreen modes? if not, simple differences in how much fillrate is being used may account for that.

- How are you measuring your FPS? Using a timer which may be using a video clock (such as hsync) internally could easily account for this.

- How are you *displaying* your FPS? If you''re using GDI (i.e. TextOut() etc) or anything which uses those internally, then that''s a performance clouding issue. I''ve seen apps in the past where occasionally 10fps hits were all down to GDI calls to display the frame rate!

- Are you triple buffering ?

Simon O''Connor
Creative Asylum Ltd

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