Summary
On my Mac, the OpenClaw chat interface appears to trigger extremely high WindowServer CPU usage and makes the whole system feel slow. The issue seems tied to the OpenClaw UI being visible on screen, not just the process running in the background.
Environment
- OpenClaw app: 2026.4.8
- OpenClaw channel: stable
- Gateway: local
- macOS: 15.7.6 (24G707)
- Kernel: Darwin 24.6.0
- Machine: iMac16,2
- CPU: 3.3 GHz Quad-Core Intel Core i7
- RAM: 16 GB
- GPU: Intel Iris Pro Graphics 6200
- Display: built-in Retina display, 4096 × 2304
- Boot setup: OpenCore-enabled system
- SIP status: disabled on this machine
Observed behavior
- The Mac became noticeably slow and laggy.
- WindowServer CPU usage rose very high while the OpenClaw chat window was visible.
- Hiding the OpenClaw app caused WindowServer CPU usage to drop dramatically.
- Memory pressure was normal, with plenty of free RAM and no swap usage.
Measurements
When OpenClaw chat window was visible:
- WindowServer: roughly 330% to 380% CPU
- OpenClaw app: roughly 1% to 8% CPU
- openclaw-gateway: roughly 1% to 6% CPU
- No swap in use
- Plenty of free memory remained
After hiding OpenClaw:
- WindowServer dropped to about 16.5% CPU
- OpenClaw remained running, but UI-related load disappeared
- System responsiveness improved
Conclusion / suspicion
This looks like a UI rendering/compositing issue in the OpenClaw chat interface, rather than:
- a gateway problem
- a RAM shortage
- general CPU saturation from backend processing
Because the problem changes sharply when the OpenClaw window is hidden, it seems specifically related to rendering the visible chat UI.
How to reproduce
- Launch OpenClaw on this Intel Retina iMac
- Open and keep the chat interface visible
- Observe system slowdown
- Check Activity Monitor or
top
- See WindowServer CPU climb very high
- Hide OpenClaw
- Observe WindowServer CPU drop significantly
Notes
This may be more visible on older Intel Macs with high-resolution Retina displays, especially OpenCore-enabled setups, but the behavior still seems like an app-side rendering problem because the difference between visible and hidden state is so large.
Summary
On my Mac, the OpenClaw chat interface appears to trigger extremely high WindowServer CPU usage and makes the whole system feel slow. The issue seems tied to the OpenClaw UI being visible on screen, not just the process running in the background.
Environment
Observed behavior
Measurements
When OpenClaw chat window was visible:
After hiding OpenClaw:
Conclusion / suspicion
This looks like a UI rendering/compositing issue in the OpenClaw chat interface, rather than:
Because the problem changes sharply when the OpenClaw window is hidden, it seems specifically related to rendering the visible chat UI.
How to reproduce
topNotes
This may be more visible on older Intel Macs with high-resolution Retina displays, especially OpenCore-enabled setups, but the behavior still seems like an app-side rendering problem because the difference between visible and hidden state is so large.