and I also read fsimon's solution. But I dont have an overclocked pc.
Maybe that's part of the problem?.. :)
I checked your log now that you uploaded one, I am 100% convinced the cause is what I mentioned above..
However I'm not sure whether it was mentioned, but before you try anything else, make sure that your power management settings are set to high performance in windows (I don't see your CPU boosting at all)
What's happening thou is your game caps your CPU core (whatever is available to it, either because it's limited by power management or by what the specific game can use) and OBS can't grab the frames.
To explain it in a bit more detail, here's what's happening.
- You're playing a game, you either have the FPS uncapped OR have it capped at too high of a value. When I say "too high" that is relative to the game and your pc ofc.
- If that is not a modern 64 bit game with proper multi-thread optimization, then sadly it will happen even at 60 fps, why? Because the game would be limited to accessing only 2 of your CPU cores and they're not even overclocked so you have a 3.6 Ghz ceiling on them
- On your stock settings, when required, your CPU should be able to boost a single core to 4.4Ghz (might not be the one used by the game), when a more spread out performance increase is needed, the other stock boosting option would be to boost all cores to 3.8 Ghz. (Neither one seems to be happening in your log hence why I think you're on a power saving profile or something)
- Either way when your individual core gets capped that the game uses OBS simply "cannot see" what's happening in the game, it's like blindfolding it so it just keeps re-encoding the same frame over and over till it gets a new one (your game will still run smooth for playing, your recording will be stuttering)
You can simply check this btw as you're recording it by opening your task manager (ctrl+shift+escape), going to the Performance tab, right-clicking the graph on the right of the CPU tab and selecting "Change graph to -> Logical processors", that way you will see CPU usage on the individual cores and you will see just how close to capped your game will push a few of them.
So possible solutions would be first of all checking that power management setting, if that doesn't help then looking at your core usage as described above and simply getting the game to use less CPU, either by capping at a lower FPS or by disabling some graphics effects which are more CPU-centric until you can see that it never even comes close to peeking any cores on the performance graph.
And lastly you could consider overclocking your CPU - actually you should consider that regardless, since the "over" part is optional and you could for example opt to get the same performance at a reduced voltage for example allowing for way less heat and more longevity, especially on a stock cooler (Ryzens run on a pretty stupidly high auto-voltage on most motherboards)
Hope some of that is helpful, again based on the log my current guess is the simple matter of the power management setting being on power saver or balanced or something other than high performance