The background flickers in 11.0a2 and 12.0a1, but not in 10.0b6. Adapter Description Mobile Intel(R) 4 Series Express Chipset Family Vendor ID 0x8086 Device ID 0x2a42 Adapter RAM Unknown Adapter Drivers igdumd64 igd10umd64 igdumdx32 igd10umd32 Driver Version 8.15.10.2555 Driver Date 10-13-2011 Direct2D Enabled true DirectWrite Enabled true (6.1.7601.17563) ClearType Parameters Gamma: 2200 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 100 WebGL Renderer Google Inc. -- ANGLE (Mobile Intel(R) 4 Series Express Chipset Family) -- OpenGL ES 2.0 (ANGLE 1.0.0.963) GPU Accelerated Windows 1/1 Direct3D 10 AzureBackend direct2d

It's still applicable in Fx 11.0b2 and 12.0a2. In 13.0a1 (32 bits and 64 bits), it's OK but there's 3 FPS instead of 20 FPS

Probably a dupe of other bugs that jgilbert just fixed: please retry in a few days or a week as his fixes are landing.

Actually, bug 7271178 and bug 724476 just landed, and are probably the ones. Please retry in the next Nightly build.

It's not so good as it is actually: * 10.0.2: 30 FPS * 11.0b4: 23 FPS, background flickering * 12.0a2/20120226: 23 FPS, background flickering * 13.0a1/20120224: 3 FPS * 13.0a1/20120226: 15 FPS

I guess Dup Bug 727178 for background flickering Dup Bug 726396 for slowness

Let's mark it as a dupe of the first symptom.