Rendering seems to be nearly as fast under Mac OS X and Windows. The small variations may just be a drivers issue; nothing you'd notice under real-world circumstances.

Audio conversion is one heavy CPU intense task.

To find out if either the OS handles the processor more or less efficiently than the other, I converted a 35 minute long MP3 audio track (roughly 32 MB in size) into Apple's AAC format. Now, this time, I was in for a surprise: While the Mac OS version of iTunes needed roughly 34 seconds to perform the conversion, Windows 7 took nearly twice (!) as long -- the conversion finished after about 57-59 seconds, no matter how many times I ran the test. I know that iTunes is a poorly written piece of software (especially on the Windows side of things), which lags under the even most basic tasks, such as switching between playlists. So I repeated the same step under Windows, but this time I used another audio converter () to do the job.

Ojosoft is as iTunes doing the same task on the same machine.