Testing performance with the latest Nightly has shown that FishIE Tank's performance has regressed significantly. This has been happening for at least the past two weeks, but I can't pinpoint when it started. Even running 20 fish is not running at 60 FPS as it does in the release version 16.0.2. This has happened on many of our test systems, but here is the Graphics section of about:support from my laptop, which also experiences the same issue: Graphics Adapter Description Intel(R) HD Graphics 3000 Adapter Drivers igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32 Adapter RAM Unknown Device ID 0x0126 Direct2D Enabled true DirectWrite Enabled true (6.1.7600.16972) Driver Date 5-21-2012 Driver Version 8.15.10.2761 GPU #2 Active false GPU Accelerated Windows 1/1 Direct3D 10 Vendor ID 0x8086 WebGL Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics 3000) AzureCanvasBackend direct2d AzureContentBackend direct2d AzureFallbackCanvasBackend cairo

Another observation: On the latest Nightly, with 500 fish, I am getting about 40-45 FPS, but when I move my mouse, it jumps up to ~55 FPS.

In addition, running with the Gecko Profiler, the FPS jumps up to about 55-58. Turning it off, it goes back down to 40.

regressionwindow-wanted still needed here. Any ideas why the Profiler and mouse movement makes the FPS go up?

The regression window can be determined with https://github.com/mozilla/mozregression