I have 350 hours of documentary footage in Premiere, working towards an assembly cut.
I'm running premiere cc2014 on a 6 core mac pro 2013 with 32gb ram. I've experienced many performance problems with premiere that all came down to the media cache.
the media cache on this project builds to about 600GB. about 5 hours on the mac pro to "conform". The media cache is set on its very own RAID1 in a thunderbolt housing containing two RAID 1's. Once it's done conforming, the project performs flawlessly.
If i need to work on another project, say a short form project, I change the media cache location so I can keep it on the short form RAID, a whole new box. That short form project works flawlessly.
But if I try and go back to the long form project, the only option Premiere gives me is to clear or move the cache. Regardless of any choice I make - The long form project will not function at all unless I rebuild that 600GB media cache.