Once the project was fully rendered, we next hand-timed with a stopwatch how long it took the system to perform a multi-pass encode, exporting the video to a 1,280x720, H.264 file, with a 672Kbps bit rate, and 128Kbps stereo AAC-LC audio.
The Core i5 MacBook Pro managed to best the iMac on the Render Time test by a couple of minutes. Its advantage can likely be attributed to its processor's multi-core rendering capabilities when multithreading is supported, and its faster Turbo Boost speeds when thermal and power conditions permit the CPU to throttle at higher speeds.
The Encode Time test, however, had different results. In this case, the iMac was the winner by a landslide, taking just under an hour to encode the video. The Core i5 MacBook Pro took almost twice as long, clocking in at 1 hour and 53 minutes. Our four-year-old MacBook Pro took over four hours to perform this same workload. Many video editors use Final Cut Pro on their laptops--some as their primary systems, others as their secondary systems when they're away from their editing bays. Encoding video can be a very time-intensive task--and it's one where the system is often chugging away, performing this single task for hours on end. Certainly the Core i5 MacBook Pro represents a monumental improvement over the four-year-old MacBook Pro--shrinking the encode of our project down from over four hours to less than two--but when it comes to system-wide, intensive tasks like this, it's often hard to beat the power of a robustly configured desktop system. One advantage for the iMac desktop, in this test case, is its 7200RPM hard drive, versus the 5400RPM drive employed in the new MacBook Pro model we tested.