could you elaborate just a bit? And does this patch SDL or Dosbox? And anyway, can a mod move it to the patches forum, so I can find it again, when the need arises? 😀

Patch is againsd sdl, we're using a path that the sdl people don't care about
(directx backend with fast rendering).

Since the SDL people aren't likely to respond any time soon, attached is an updated DLL file that incorporates the fix (as well as the regular DOSBox-specific changes).

I'm sorry about bumping this, but why is this not included in more recent builds (namely those with direct3d output support?) Changing modes is nearly instant with this SDL.DLL compared with the stock one in ykhwong's build. At least I've noticed this is System Shock, which goes back to 320x200 whenever the main menu or map is brought up.

Please post reports ONLY against the latest official release.

There are no improvements for DOSBOX 0.74 using this DLL. OpenGL and OpenGLNB still have considerable delays when changing modes.

Still, I feel it is significant that it greatly improves performance of the Direct3D9 patch.

This has nothing to do with the speed of mode switching. All it does is fix one memory leak when using DirectDraw. It does absolutely nothing with OpenGL. Any improvements in speed are purely coincidental except in edge cases and are much more likely due to your graphics card driver. This is not a performance patch. It is a memory bugfix.