The white noise you hear in this Vine is the sound of my laptop fan whirling away at top speed. This animation is rendered in <canvas>, in Chrome. While the animation does have thousands of particles being rendered, I hadn’t expected the top-speed fan.

I’ve been able to pinpoint its cause. The animation was using the width of an image, this.img.width, for every particle, every frame. Setting this value to a separate property this.imgWidth has slowed down the fan significantly. I speculate that this issue is similar to reflow triggers.

Clearly, debugging via hardware machinations is not a good strategy. I still struggle with making sense of anything in the Chrome Developer Tools around rendering performance – especially for a rendering like this one, involving thousands of particles over thousands of frames.