My MacBook Air M2 (16 GB RAM, macOS) experiences severe lag when screen sharing in video conferencing apps (Microsoft Teams and Zoom). The lag is visible to meeting participants and makes screen sharing unusable for extended periods.
Environment:
- MacBook Air M2, 16 GB RAM
- macOS (latest version)
- Wi-Fi 6 (802.11ax), 186 Mbps down / 302 Mbps up
- Issue occurs with: Teams desktop app, Teams in Safari, Zoom
- A colleague on Windows with slower internet (124 Mbps) has no lag on the same platforms
- I’m looking for software-side solutions since replacing the hardware isn’t an immediate option.
Observed behavior during screen sharing:
WindowServerCPU spikes to 80-90%kernel_taskCPU rises to 30-50%- Activity Monitor shows progressive CPU throttling over time
- Lag worsens the longer screen sharing continues
What I’ve already tried:
- Sharing a single window instead of entire screen
- Lowering built-in display resolution
- Disconnecting external monitor
- Disabling camera during screen sharing
- Closing all non-essential apps and background processes
- Enabling Reduce motion and Reduce transparency (Accessibility > Display)
- Disabling Spotlight indexing temporarily (
sudo mdutil -a -i off) - Removing CPU-heavy background processes (
duetexpertd,mds_stores,BackgroundShortcutRunner) - Upgrading router from 802.11ac to 802.11ax (Wi-Fi 6)
- Reinstalling both Teams and Zoom
My analysis:
The MacBook Air M2’s fanless passive-cooling design appears unable to dissipate heat fast enough during the sustained CPU load of continuous screen capture (WindowServer) + video encoding. kernel_task throttles CPU to manage thermals, causing the visible lag.
Are there any macOS-level settings, Terminal configurations, or third-party tools that can reduce WindowServer’s CPU usage during screen sharing, or otherwise mitigate thermal throttling on a fanless MacBook Air M2?
