Did you read and grok the blog article, or just scan for results? Do you understand that he threw tests at the Mac Pro that he knew wouldn't take advantage of the GPUs?
From his article (all rights reserved for Larry, etc, etc)
Compressing video is not something that OpenCL (or CUDA) is well-suited for. Regardless of the application. Which means it's not something that can be thrown at the GPU. It's entirely CPU based, and in the case of the iMac: it has a faster and more capable CPU for that task at hand.
One thing I really wish Apple would publish is just what FCPX and Compressor can use OpenCL for. Adobe makes it very clear what Premiere and AME can do with CUDA and/or OpenCL. In fact, they list everything right out. Apple just says, "It'll be faster..." That is what causes confusion like this.
I read every word and that's what scares me. My main objective is to speed up the time it takes to make videos. This involves editing, rendering then compressing to the final destination, which is normally using H.264 in a QuickTime file, using Compressor, normally with a preset.
As such, under those conditions, it would seem that the main advantage of the Mac Pro is not speed, but expansion capabilities, because of Thunderbolt 2.
As you said, video compression is largely CPU based, so the 4 core in the store choked because of a lack of QuickSync. The only reason Larry's Mac Pro even came close to the iMac was because he used a 12 core. The trouble is, I'm getting a 6 core, so there's a big leap of faith that speed gains on non compression tasks and expansion will eventually justify the Mac Pro over the iMac.
Still, what I truly want is to either experience some sort of speed bump... even 20% better than my MacBook 2011, or hear from somebody who actually edits video that can testify to the fact that the Mac Pro is clearly faster doing the kinds of everyday things I do... edit, render, then compress to a final product.
Without posting video to use as a baseline, my test is similar to the BruceX concept, using built-in generator clips and filters. I drag "Pages" from the generator onto the timeline, change the duration to 8 minutes, then drag the "Clouds" titles to the start and extend it to 8 minutes, then apply the "Romantic" effect to the "Pages" clip. I time the renders, then compress with Compressor with a preset Apple Devices HD (better quality).
The MacBook 2011 does the final step in about 3:15, but as I said, the new Mac Pro took nearly 60 minutes. If anyone wants to give that test a shot, it will at least tell us that the GPU has some benefit.
