I recently installed Apple iTunes for the first time (the QuickTime install on my laptop was having lots of problems). One of the first things I tried out was subscribing to a video podcast (specifically The Totally Rad Show), which was fairly easy to do. As soon as I started to play the latest episode, I noted that playback performance was horrible. I never had this kind of performance problem with QuickTime, so I was a little surprised that iTunes would be so different.
A quick Google search turned up a support article from Apple on iTunes performance in Windows XP and 2000. All of the standard suggestions are there (make sure you're computer is fast enough, download the latest version, etc.), but one suggestion caught my eye: "Disable Direct3D video acceleration in QuickTime."
I ventured to the Windows Control Panel, opened the QuickTime item, and turned off the Direct3D video acceleration. To my surprise, performance was restored! Who knew that a simple toggle could solve such an annoying problem?
In loosely related news, I'm getting closer to actually buying an iPod (something I thought I'd never do). More on this later.
You don't know the power of the Dark Side; I must obey my master. — Darth Vader