My KSP performance comparisons: platform and graphics mode

[Wercho]

So, I've been doing some vague benchmarking to see how I can get the best performance from KSP. To that end, I have been using Kerbokatz' FPS Viewer and Physical Time ratio viewer to see how the game is running under different platforms. I've got KSP installed on Windows Vista and Linux (Ubuntu 15.04). I flew the Dynawing stock craft, and watched the reported Physical Time ration, and here are the results:

Physical time ratio, using a physics time step of 0.02. (Higher is better).

Windows Vista, DX9: ~58%

Windows Vista, DX11: ~50%

Linux x64, OpenGL: ~50%

Windows Vista, OpenGL: ~35%

 

So, with my hardware, DX9 gets the best performance (though at the cost of higher memory usage as others have discussed). DX11 and Linux OpenGL, and Windows OpenGL is significantly worse.

Another thing I noticed: Under DX11 and OpenGL, the performance drops to about 25% at the default zoom, but if I zoom out just a bit (so the craft fills about 1/2 the screen vertically) the performance increases to the above values. This doesn't happen on DX9. It performed the same regardless.

Lastly, Physical Time Ratio Viewer has an option to display the physics time-step. I noticed that if I increase the physical time-warp, the physics time step goes up proportionally, but then doesn't come back down when reducing the physics time warp. The effect on performance is noticeable, so I don't think it is just the mod not recording it correctly. It seems like the mod is getting it right, and the game isn't resetting the physics time-step when warping down.

Computer specs, for the curious: Intel Core 2 Quad Q9550 overclocked to 3.78GHz; Nvidia GTX 960, playing at 1080p with a few graphics mods (EVE, scatterer, Real Plume).

Anyway, these are just some observations I made. Maybe they'll help someone else figure out how they want to run their setup.