Elgato Turbo.264 H.264 encoder
The figures speak for themselves: Turbo.264 is way faster than the host Mac. While the unaided MPEG Streamclip took just short of 23 minutes to encode the six-minute clip, Turbo.264 did it in just under seven minutes, less than a third of the time.
H.264 encoding: CPU vs Turbo.264
Shorter bars are better
You can see from the image results Turbo.264 produces a slightly darker, higher contrast image than the original, but watching the results playing back - as opposed to squinting at single frames - is no different from viewing the original. Turbo.264's output might not pass pro video muster, but it's unquestionable fine for iPod, PSP, Apple TV or computer playback.