How to fix performance issues?

To my understanding, porting games to Chowdren is very difficult. It may also not support all of Knytt Stories' plugins.

Oh ok, that's unfortunate.

Does then normal 1.3.7 not run as well as 1.3.6? You only listed 1.3.7-1080 in your bench tests. I was under the impression it was the very fact that I changed the native resolution of the game to match your monitor that trapped you into the bad frame rate.

You can't raise the frame rate of the game without reprogramming everything. The frame rate is used for timing on most aspects of the game. I don't know anything about Ultimate Fullscreen or Chowdren, and I'd rather keep it that way. I'm not actively developing KS+ anymore, and I can't stand working with MMF2. I'm mainly just doing maintenance. Major overhauls aren't going to come from me. The KS+ source is available up to 1.3.6, and there are several remakes in the works. Also Win11 is on its way, there's no telling what surprises it will hold for old programs.

I just tried 1.3.7. There was some lag but not as much as the 1080 version. The fullscreen is not smooth like the 1.3.6 one. From my experience, 1.3.7 runs way better when set to 50hz in comparison to previous versions, for some reason.
Any idea why the 1.3.6 fullscreen runs smooth?

Wait, what are the other remakes besides YKnytt?

I will try Win 11 on one of my computers at some point to see if it changes anything and if it's worth it in general. I don't know when though.

There are only minor differences between 1.3.6 and 1.3.7. I added some logic to improve the menu that only runs on the first cycle when you load a game, the search bar in the level selector behaves differently, and the screen edge glows green with the detector. This last one could cause an extremely small increase in processor need, but I doubt it would change frame rates. Now that I'm thinking about it, I can make that lighter. It paints the image now. I'd be faster if I added a pre-rendered green version. The v-sync switch does nothing unless you select it, so if you leave it alone it shouldn't bother anything.

yknytt is the only recent attempt I've heard of, but there have been other starts. KSDS is complete, but it's Nintendo DS homebrew. Not sure how it performs in emulation.

Ok. The fact one of those things could affect fullscreen performance is really weird to me.

I read the KSDS manual. Community levels require music and ambience ogg files to be converted to mp3 and raw respectively, with a much lower sampling frequency. Being an "audio guy", I really don't think I could bear the difference in sound quality (and converting sound files in 100+ levels is not something I personally would do anyway).
It has no map. I almost always force your nice map in large non-linear levels.
Also it probably doesn't support levels made in your mod.

I think a finished YKnytt with all issues fixed would be a good "solution", but the latest update is dated feb 2020 and it doesn't seem to be active.

I had a thought: if you manage to fix the 1.3.7 fullscreen regression, maybe the 1080 fullscreen would also stop lagging?

I just tried the 1.3.7 fullscreen again and it was almost running smooth like the previous one (lag is occasional, I guess?). The 1080 version still lags though.

That's good. I mean it's not good, but I'm glad I didn't break the mysterious set-up that allows KS+ to run better sometimes.