[pcwalton]

I actually think that CSS is better for drawing with modern GPUs than native UI frameworks are. CSS is declarative, which enables global optimizations--very important on GPUs, where state changes are expensive and overdraw hurts. By contrast, native UI frameworks were designed for slow CPU rendering in the '90s via legacy APIs like GDI.

[skrebbel]

I believe you, but still my layman's observation is that the average cocoa/win32 ui feels much snappier than the average web app. I have no proof but I'm pretty sure most people here would back me up.

If it should be faster with CSS, why isn't it? In fact, I develop a web app. What am I doing wrong?

[pcwalton]

Because browsers are not currently architected to make good use of modern hardware.

[wander_homer]

Maybe because the GPUs aren't used efficiently with the current technology. E.g. Webrenderer for Servo was designed to make great use of GPUs right from the beginning and the first results are really impressive.