It's obvious you're fishing, but whatever.
First off, they're using Boot Camp which is notoriously more taxing on graphics hardware due to poor implementation.
Secondly, you're using itunes. This a program that comes installed on OS X, yet on Windows, it is (purposefully?) poorly coded and like an infestation, installs other Apple software. They should have used VLC if they wanted real world results. Using itunes is a joke, and not just because it's a joke of a program.