Is the issue still on?
I had various stuttering issues with windows 8 RTM, that all of them was solved by simply enabling hyper-v on windows "programs and features" > "Turn Windows Features ON or OFF" (under control pannel, programs).
It was unacceptable that windows 8 (which is suposed to be faster than windows 7) could not do some simple tasks, like playing a song or browsing the web, without stuttering alot, so I googled and found the answer.
I found the answer on a blog, I don't have the address, sorry, but it helped alot, expecially with firefox.
Anyone who got any stutter under windows 8 should give it a try, although I don't know if this hyper-v feature does anything at all, but it solved my problem.