In this video Dave Helmly gives you a quick tour of Apple's New Mac Pro running Premiere Pro CC in various workflows including Multi Layer GPU Effects, 4K, Mixed 4K timeline, the power of Dual GPU Exporting vs CPU (software/CPU) , and finally GPU based Debayer for Red RAW R3D files. Also featured in the video are a quick peek at the new LG 21:9 UltraWide QHD Monitors , Promise Pegasus 2 Raid, LaCie Little Big Disk Thunderbolt 2 and more.Special thanks to Sony, Panasonic, Mammoth HD and Devin Supertramp for the use of their footage.
More info here: blogs.adobe.com/davtechtable/2014/03/working-with-premierepro-cc-the-new-mac-pro.html
[UPDATE July 1st 2014]
We (Adobe) are aware of an issue affecting users of Adobe Premiere Pro CC and Adobe Media Encoder CC on Mac OS X 10.9.3. As of today, Apple has released OS X 10.9.4 which appears to address the issue.