Also core count is increasing, but raw speed per core really isn't. Multicore really doesn't help web rendering very much. Nearly all javascript out there is single threaded and most dom rendering is too.
Raw speed per core is increasing DRAMATICALLY in mobile. Faster than even Moore's law would dictate. As the die process has shrunk, more transistors are fitting within the mobile TDP ceiling so modern processor methods are finally getting used. As recently as the ARM A8, out-of-order execution wasn't even used!
You can verify that this is correct by looking at any benchmark.
Indeed. Blossom[0], a mobile MVC client framework for business apps, is being updated as we speak to split apps into a UI/animation thread, with the application/model layer/network in a web Worker on a separate thread.
That's really not a rebuttal. Yes, lots of browsers now support web workers. Yes, it is therefore possible to write multithreaded javascript. And that may become more common over time. But for now, the fact that it's possible does not change the fact that nearly all javascript is still single threaded.
IE10's chakra engine parallelizes interpreted javascript execution (on page load) with JIT compilation and garbage collection. So you can have up to three cores at work executing javascript even without web workers. Meanwhile, the rendering subsystem offloads to the GPU, and the whole thing can exist multiple times for multiple tabs, potentially involving dozens of cores executing your web apps.
