Macbook Pro M4 Max getting encoder lag

[nekka]

Hi

Since I updated MacOS to Tahoe 26, I've been unable to stream. I'm getting both render & encoder lag. I had been streaming from the same Macbook all year with no issues until September when the MacOS Tahoe update rolled out. Ever since then it’s been issues one after the other.

One thing that did help for some time was switching to the Metal (experimental) renderer. That had it run smoothly again, up until I went away on a trip.

When I got back, MacOS had updated, OBS had updated and now it’s not working anymore. (Obviously the Metal renderer is experimental so instability is to be expected, but the generic problem still exists)

I have noticed the issue appears to initiate / get worse when I have a desktop sharing scene and/or I click out of OBS. So whenever OBS is not in focus, it starts spiraling with render/encoder lag.

Does anyone have any more ideas I could try? I'm about rock bottom at this point.
Here is my log file: https://obsproject.com/logs/kxDViI9I0q2LsJYR

Not sure if there's anything else that would be useful to add here, please let me know. I've tried to add as much detail as I can think of, but this isn't my area of expertise.

HARDWARE
Macbook: Macbook Pro M4 Max / Model A3185
CPU: 16 cores
RAM: 48GB*
GPU: 40-core

SOFTWARE
MacOS Version: Tahoe 26.0.1
OBS Version: 32.0.1

PLUGINS
Source Record
Aitum Vertical
Quick Access Dock
Source Clone
Stream Deck (for OBS)
Source Profiler

SETTINGS
Canvas size: 1080p
Output size: 1080p

STREAMING
I am streaming to the following outputs:

• Output to Twitch

RECORDING
I am recording the following scenes:

• Output to Twitch
• Art cam

 

[Talonis]

That is odd. Have you tried:

1. Switching off all plugins
2. Re-installing OBS Studio
3. Reformatting your machine?

 

[nekka]

Hi, thanks @Talonis for your reply

I found the solution in the end. I have a 4k monitor connected, and for some reason, since updating to MacOS Tahoe, it doesn't handle screen sharing well at all. The performance skyrockets and I run into encoder / render lag. I was running a test stream without being connected to my 4k monitor the other night, and it ran fine. I tested it while connected to the monitor again, and the lag came back. I then tried lowering the resolution of my 4k monitor, and it ran smoothly. I have now run 2 successful streams just by lowering the resolution of the 4k monitor.

I do think this has something to do with how OBS / MacOS handles screen sharing since the update. If you run OBS and "cull" the screen shares from Apple's menu bar shortcut, it stops the lag. Something changed since that update to Tahoe, because it was never a problem before. In any case, it's not a problem for me now, since I can just lower my monitor res and it's fine, but I thought it might be a worthy mention