Micro-stutter or just "frame skips"?

[whitestar]

I have a fairly good understanding of what micro stuttering is and why it occurs. Have a look here for reference: https://www.pcgamer.com/what-is-microst ... -i-fix-it/. And here: https://testufo.com/stutter#demo=micros ... 00&pps=720.

But in Trials Rising I am now experiencing something which I'm not sure what to call. I'm trying to find a term for it. The best way I know how to put it is "frame skipping at fixed intervals". The "skips" are once every 0.8 seconds or so. And they happen at a fixed interval.

Something like this (where the hyphens are silk smooth motion):
-------stutter-------stutter-------stutter-------stutter------- and so on.

There's totally silk smooth motion for about 0.8 seconds, then the graphics "skips" ahead a couple of pixels, then totally silk smooth motion again for about 0.8 seconds, then skip, then....well you get the picture. Those "skips" are very visible and fairly distracting.

This type of behaviour is not exemplified at the testufo site either. But I think I once saw a slow motion capture from Skyrim which showed similar behaviour.

The best way to see it is to try Trials Rising with v-sync on and Fullscreen. For some reason though the stuttering is gone when I use Windowed or Bordeless.

So:
1. What is this phenomenon? Does it fall under the micro stutter category?
2. Why does it happen in fullscreen and not in windowed mode?

Would be nice to have your thoughts on this.
Oh and Chief Blur Buster, is this something you could make an example for on the testufo site? If you know what I'm talking about that is.

Cheers

[Chief Blur Buster]

Well, it's hard to come up with a name for it, but I'd say "cyclic stutter". A rotating cycle of smooth-stutter patterns.

Sometimes this is caused by an interaction with the game's internal vsyncing mode with the drivers' configured vsyncing mode -- e.g. drivers set to VSYNC ON but in-game set to VSYNC OFF. Are the driver settings configured to "Application Settings"? And Game settings configured to VSYNC ON? Or driver settings configured to "VSYNC ON" with game settings configured to "VSYNC OFF"? I've seen some weird interactions occur from a divergence.

Sometimes it doesn't happen, it depends on how the game engine is programmed.

[whitestar]

Cyclic stutter is a good name for it I think.
I'm pretty sure drivers are set to Application Settings (will double check), and in-game to vsync on. And yes, it only happens with vsync on.

I've seen this phenomenon before but I can't remember in which game, as it's pretty rare nowadays.

Is this something you could exemplify on your testufo site? As in make it a selectable option in the Demo: dropdown list? It would make it a heck of a lot easier to explain to devs when this occurs.
I wonder if it will show in a YT video. In theory it should, if I record at 60fps.

[RealNC]

Witcher 1 also has it. It's usually just a game bug, unless it happens in every game.

[Chief Blur Buster]

Yup. Alas, game bugs.

Sometimes they try to do clever tricks to try to smooth frame rates on certain systems, but create side effects.

Sometimes KitchenSync is the problem...
There's SO many different sync technologies now. Kinda complicates things for some game developers. A universal framerate smoother is extremely hard to program, considering the variety of hardware & software sync technologies (VSYNC ON, VSYNC OFF, GSYNC, FreeSync, Fast Sync, Enhanced Sync, ACME Sync, KitchenSync! Joke... But seriously, I am a software developer, and I can tell ya.... when you optimize a videogame for one sync technology, sometimes you make the game worse for other sync technologies. Or you increase lag. Or some other dominoe falls. Whac-a-mole game optimization.

You could simply add buffers or frame queue (prerendered frame queue) -- and a lot of it is fixed since the queue makes it easier for all the sync technologies perform smooth. But once a game developer tries to program the game in a way to reduce lag and or smooth stutter for one specific sync technology, you start to get forced to optimize differently for the different sync technologies. Ouch.

For example, doing the low-lag VSYNC ON tricks and then using VSYNC OFF, will create problems such as stationary tearlines and such.

Interesting Reading: This is a present-day problem at the moment. Looking to the future, see Blur Busters Law: The Amazing Journey To Future 1000Hz Displays. By 2030-2040, when 1000Hz monitors make sync technologies unnecessary (Did you know that VSYNC ON, VSYNC OFF, FreeSync, GSYNC all look darn nearly equally identically tear-free, smooth and lag-free at 1000Hz?) we won't need to talk about this. The higher the Hz, the more the sync technologies converge together. Sync exists because of the humankind invention of using a series of static images (frame rate, refresh rate) to simulate the impression moving images. But for now, universal low-lag stutter-free game optimization for all sync technologies is a hellish exercise.