Recording framerate drops dramatically when expanding a window


New Member
I'm not very experienced with OBS, or any technical stuff, honestly, but this is a problem that I can't find an answer to anywhere. I'm attempting to record myself playing Minecraft, but the framerate of the recording drops to maybe 3-4 fps whenever I expand the window to full screen. I've experimented a bit, and here's what I've discovered -
- If I have the Minecraft window covering approximately a sixth of the screen, the framerate is perfectly smooth, presumably between 30-60 fps
- Increasing the size of the window from there slowly decreases the framerate until full screen when it's running at 3-4 fps
- The lag occurs in the OBS preview and in the finalized recording. It has no effect on the game whatsoever.
- The sound is completely normal
- Lowering the framerate I'm recording at, even to a ridiculous level (I tried 100x50 just to check if this was the issue), has no effect on the frames at all
- Lowering the canvas size, changing the encoder preset, capping the in-game framerate, and capping the recording framerate also have absolutely no effect

I just recently installed OBS, so most of the settings are exactly what you'd expect. I have only one source (Minecraft), one scene, etc. The only things I've changed are the video format from .mkv to .mov because my computer refuses to open .mkv videos, added Soundflower 2ch as an audio source, scaled down the resolution to 1280x720 because I thought that was what was causing the fps issue, and added 2 hotkeys.

I've also tried a lot of the typical fixes you find with a quick Google search, and none of them have done anything. The logs also don't show that many frames have dropped (stating that 1189 frames were output despite me receiving significantly fewer- doing the math shows that 1189 frames in a 20 second video should have been approximately 59.5 fps):
"17:02:38.709: Output 'simple_file_output': Total frames output: 1189
17:02:38.709: Output 'simple_file_output': Total drawn frames: 1218 (1228 attempted)
17:02:38.709: Output 'simple_file_output': Number of lagged frames due to rendering lag/stalls: 10 (0.8%)"

My specs are as follows (sorry if I missed anything important or added anything unnecessary; as I said, I'm new to this):
MacOS Catalina, v. 10.15.7
Processor: 3.6 GHz 8-Core Intel Core i9
Memory: 16 GB 2667 MHz DDR4
Graphics: Radeon Pro 580X 8 GB

Log file is attached. The edit was me removing personal information. I didn't change any of the important data.


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