Nope.
I bought 2012 Mac Pro 2 x 3.46 GHz 6-Core, 64 GB and the stutter still occurs, although usually in much "pleasant" way - the video playback stops for about one second and than plays back again. Previously occurring stutter still appears on movement, when there is a slow pan or something like that, the video gets a hiccups.
As if that wasn't enough, I have now the entirely new problem, that appeared after the computer change - extremely frequent "PT quit unexpectedly" and memory errors. I made whole bunch of screenshots of the errors I get, that you can see on my flickr gallery:
https://flic.kr/s/aHskokkbaF
You can see there also a System Usage window which shows constantly between 17 and 20% of CPU (Native) usage and activity monitor floating window during playback.
These errors make me mad and totally ashamed when someone (i.e. director or producer) is coming to see my work. What's worse, I'm close to the end of mixing the feature and at the moment can do nothing to solve this problem.
My session gets bigger and bigger. At the moment I have 53 instances of Pro Q2 and 20 of Altiverb. Lot of sends and about 120 tracks (mono, stereo and 5.1). I would believe, that non HD PT with CPTK is not capable to handle it, but yesterday I created new session with just a few tracks and 2 VI (Play) instances. The performance was also very sluggish and CPU errors was occurring every few minutes of work.
If someone has any idea of anything safe enough I could do to at the moment to stop these errors, please, please chime in!