Google Chrome 18 has been pushed to the stable channel bringing with it two big new features, both related to graphics. On the one hand, HTML5 Canvas content is going to be hardware accelerated. On the other, it is now possible to run WebGL content without hardware acceleration.
"We’ve enabled GPU-accelerated Canvas2D on capable Windows and Mac computers, which should make web applications like games perform even better than a pure software implementation," Google explained
In practice, this means that 2D content running in Canvas will perform significantly better, boosting the performance of 2D games or apps that use the technology. Most 2D graphics shouldn't stress the CPU too much, but it's best to offset this type of job to the GPU which does it much better.
There may still be issues with Canvas hardware acceleration, but they should be isolated enough; otherwise, the feature wouldn't have made it to the stable channel. Note that the feature doesn't work on Linux yet as it's too unstable.
But Chrome 18 also makes sure that as many people as possible enjoy the modern web by enabling a CPU-powered software rasterizer for WebGL, meaning that 3D graphics will work on your computer even if your GPU is not supported or your drivers are too old.
Granted, WebGL content can be rather taxing on your computer as it is, running it on your CPU is probably not going to yield great results. At the very least though, simple graphics should run smoothly or at least be usable. Though most of the demos around make it a habit of showing off what WebGL is capable of, meaning they're fairly demanding.
But by the time WebGL starts being used for more than just tech demoes, a CPU fallback option should be handy.