I have edited several long documentaries with no problems on rock-solid Premiere Pro6. Decided to subscribe to the Cloud and downloaded CC2014 mid-project. Switched from my NVIDIA Quadro 4000 card to a Sapphire Radeon 7950 Mac Edition (3GB GDDR5) card to keep my 3 monitors enabled. (It was the only card approved for CC use and that would work with my mid-2012 Mac Pro) The playback is incredibly sluggish (until all the thumbnails have loaded) and will lag behind after a few minutes of play. If I move down the sequence 20 minutes it will take seconds before I see an image. If I turn thumbnails off, performance is greatly improved (but who can edit like that?) I have tried everything (emptying the cache, changing sequence settings, changing permissions) and spent 1.5 days on the phone with adobe tech support and NOTHING fixes this. I am so disappointed and ready to return to PPro 6 until this job is finished and I decide on a new computer. Any last ideas? Thanks for any help.
2.2.4 GHz 6-Core Intel Xeon
32 GB RAM
Postscript: downloaded CC2015 hoping it would work better and it was worse. The Sapphire 7950 is not on the "approved list" yet for CC2015. Uninstalled and returned to CC2014. I am so disappointed.
Postscript2: Playback was equally sluggish when working with the NVIDIA Quadro 4000 card using only 2 monitors. I was hoping the new card would resolve the lagging and bumpy playback.