I wonder if everyone will jump on the CUDA bandwagon... This is what irks me about Safari on the rMBP. You've already got a chip that's massively powerful in the machine and which supports CUDA. By using that technology, you should be able to eradicate any browser lag. The computational power in CUDA can be used for practically anything (biocomputing, encryption, image rendering, etc.). Certain programs used in Biocomputing already perform calculations up to 20 times faster with CUDA enabled. So why not use this same technology to enhance the daily browser experience? The answer seems obvious to me: Apple is pro-OpenCL, and Nvidia is obviously not. So I'm not sure we have the right chips in our machines. I wouldn't be surprised to see Apple ditch Nvidia at some point in the future.
Safari lag has already been fixed. Install Webkit nightly.
As for OpenCL and CUDA, most of what they accelerate involve linear math that benefits a lot from threading (splitting the algorithm into different parts and processing each part in parallel). Typically, that's a lot faster (about 2-10x faster) than regular CPUs. But when it comes to branching (if, else, logical statements, that sort of thing), they have to branch, or warp within the GPU, and that usually results in dropped performance. Markedly so.
In fact, in some cases, CPU might well be faster than GPU when it comes to branching (logical operations).
Unfortunately, Safari and other such browsers rely heavily on logical operations. Especially when it comes to interpreting or recompiling Javascript. So they won't benefit at all from CUDA or OpenCL.
Unless, of course, you're talking about a website that's purely made up of a ton of images... but even then, those are rare, and in most cases, branching operations still affect performance a lot more while scrolling and navigating than shaving a few seconds off of loading a big image.
