MicrosoftEdge
[Problem/Bug]: WebView2 Runtime 142: Significant rendering performance degradation for canvas elements at 4K resolution and above
What happened?
After updating to WebView2 Runtime 142, our application using stacked canvas layers (WebGL → 2D → 2D) experiences severe rendering performance degradation. The issue occurs only at canvas widths ≥ 3840px (e.g., 3840×2160, 3840×1440), where FPS drops from ~160 (Runtime 141) to ~50. DOM rendering also becomes noticeably stuttering. The problem persists across OS reinstall, driver reinstall, and code rollback. Downgrading to Runtime 141 resolves it immediately; upgrading back to 142 reproduces the issue.
Due to project constraints, browser testing isn't feasible.
Importance
Important. My app's user experience is significantly compromised.
Runtime Channel
Stable release (WebView2 Runtime)
Runtime Version
142.0.3595.65
SDK Version
No response
Framework
Other
Operating System
Windows 11
OS Version
10.0.26100
Repro steps
- Use a desktop app with three stacked canvases of the same size: WebGL layer → 2D layer → 2D layer (e.g., 3840×2160).
- Run on Windows 11 (24H2/25H2) with WebView2 Runtime 142.
- Test at different resolutions:
- 3840×2160 → FPS drops to ~55
- 3840×1440 → FPS drops to ~55
- 3200×1800 → FPS remains stable (~160)
- Downgrade to WebView2 Runtime 141 → performance returns to normal.
Repros in Edge Browser
No, issue does not reproduce in the corresponding Edge version
Regression
Regression in newer Runtime
Last working version (if regression)
Runtime 141
can you provide a simple sample app which reproduces this issue in 142 and not in 141?
We have exactly the same issue with our app using a similar kind of stacked 2d/3d canvas set up as described here.
In our case it's 2x WebGL canvas' laid on top of a single 2d one.
It's gone from being a solid 120+ fps in 141, to being nearly unusable in 142.
From what I can tell, the issue appears to be with the 2d canvas rendering, as disabling hardware acceleration for 2d canvas fixes it immediately.
Also, just to confirm.
The issue is also now present in both Chrome and Edge, now that Edge been updated to version 142.
Thanks for reporting the issue. @GordoRank, @mg-chao, Can you please share the sample repro page where the issue can be repro-ed?
I have exactly the same issue with some templates that use 2d drawing. for example check out this url:
https://vincentgarreau.com/particles.js
when I open it with firefox or older versions of edge or chrome I get 144fps. but with latest version of edge and chrome I get around 50fps. It even causes the browser content to flash when used in some templates in the latest version of edge and chrome.
Edit: I also confirm that it happens only in 4K resolution. After making browser window smaller it returns to full fps.
