Funny you ask! I have 3 Macpros all set up the same way. The new 12 core is handling the SAME footage on the SAME hard drive the SAME way you are describing. I shot footage with my varicam and 5D. The DSLR footage is causing huge problems. It stutters like hell in the VIEWER window only. The canvas is fine. I also get out of memory warnings. Crashes. Mostly when I am applying Magic Bullet effects and Twixtor. It is like I am using FCP Version 1.
HERE IS THE KICKER:
APPLE SENT ANOTHER 12 CORE AND THE SAME THING HAPPENED WTH THEIR STOCK DRIVE IAND FCP CLEAN INSTALL. WHY?????
I have been an apple user for over 15 years, Final Cut pro user since the beginning. This HAS to be a hardware issue since my other macs are acting okay with NO JUDDER in the viewer window with the same footage and very little crashes.
HELP!!!!