CPU usage is very high even when not recording

[Min]

Hello,

I am encountering a very strange problem. OBS worked just fine until yesterday. Today I rebooted my computer, then OBS starts to use insanely high percentage of CPU when recording a game I am developing:

1. Recording: ~160% CPU;
2. Not recording, but game is running: ~80% CPU;
3. Not recording, and game is not running: ~20% CPU;

For the last scenario, even though OBS's status bar shows only ~3% CPU usage, the OS "top" command shows it is actually using ~20% CPU.

I tried a new installation and a new version of OBS, with a clean new scene, the problem seems to persist. I have no clue how this happened. The problem showed up only after I rebooted my computer today. With the same settings, its CPU usage used to be half of the current usage when recording, and about quarter when not recording.

I would really appreciate if someone can help me to solve this problem. Thanks!

 

[Lawrence_SoCal]

160% CPU... too funny... gotta love Apple sometimes (not often, but this is one of those long running silliness items) anyway ...

Realize that when OBS is running (not recording are streaming, just open, you have scenes and sources, etc) that you are doing the computationally demanding task of real-time video encoding (as it is rendering in the OBS app). That load can be doubled if you are in Studio Mode (ie render 2 screens)
I suspect is you turn off/disable/don't display your video source (windows capture), your CPU usage will drop dramatically.

No, whether an OS update, browser update? or something else, caused the change is hard to say
As for that CPU load on a 3 generation old ultra-low power CPU, re-scaling video (base res at 1440p but canvas at 1080p) 60 fps.. I'd say 20% CPU load for OBS sounds reasonable. Then log shows browser hardware accel disabled.

And that log doesn't have a record or stream (required to collect/display other metrics)

 

[Min]

160% CPU... too funny... gotta love Apple sometimes (not often, but this is one of those long running silliness items) anyway ...

Realize that when OBS is running (not recording are streaming, just open, you have scenes and sources, etc) that you are doing the computationally demanding task of real-time video encoding (as it is rendering in the OBS app). That load can be doubled if you are in Studio Mode (ie render 2 screens)
I suspect is you turn off/disable/don't display your video source (windows capture), your CPU usage will drop dramatically.

Right, turning off the video source reduces CPU usage dramatically.

No, whether an OS update, browser update? or something else, caused the change is hard to say

No OS update. All browsers were closed before rebooting, and after rebooting, no browsers were opened, in fact, only a couple of non-system applications were running. So it was also unlikely due to browser update. But I could not rule out the possibility that something was updated automatically during rebooting, I also suspected this, but couldn't figure out what.

As for that CPU load on a 3 generation old ultra-low power CPU, re-scaling video (base res at 1440p but canvas at 1080p) 60 fps.. I'd say 20% CPU load for OBS sounds reasonable. Then log shows browser hardware accel disabled.

Right, my OBS configuration for recording was a bit too much for my laptop. In fact, I used to use mostly the default parameters in my configuration, it worked just fine until several weeks ago, when I started to notice some apparent quality degradation in my recordings. At that time, my recorded videos started to have quite some significantly blurred frames for scenes with rapidly changed backgrounds. My previous recordings show nothing like this (at least not so visibly).

Then, I began to test other parameters to record high quality video to avoid that blurring issue. And to my surprise, with these high quality settings, recording with OBS on my laptop was still acceptably smooth. So I decided to keep using those parameters. Now after that rebooting, I can no longer record smoothly, the game become very laggy during recording.

And that log doesn't have a record or stream (required to collect/display other metrics)

Now I attached a new log file for multiple recordings. The first recording used the same configuration parameters as those used before the issue appeared. The I reduced bitrate from 8000 to 6000, and then to 5000. I also changed the encoder from 'x264' to Apple's hardware encoder. With these new parameters, recording is no longer so laggy, but still not as smooth as before.

 

[Mark Weiss]

I had the same thing happen here on Windows just now. OBS typically uses 2.8% to 3.3% CPU before the reboot, but since rebooting, it's now hitting 16% to 19%, no matter what source, and even when idle and not streaming. Just a reboot did this. Or was it incorrectly reporting low CPU use before I rebooted?