I'm editing a documentary feature using Premiere Pro CC V. 8.1 (latest updates, as of today), and, lately, whenever I load my project file (which is about 8mb, and contains around 8000 separate clips, 60 hours' worth), it takes my system (which is very new - 16GB of RAM, Intel i7, NVIDIA 970, etc) a really long time to load all of the media after the project file's been opened. It used to only take a minute or two, but I'm sitting here fifteen minutes after I've opened the software and I'm about 1/8th of the way through. No new media has been added recently, and very little has been edited - so no effects, or anything. There's a decent amount of synced multicam content, about 50 sequences worth - but that's it.
-Source footage is h264 sourced from a GH4 and 60D as well as M2TS files sourced from a handicam. Mostly 1080p, some 4k.
-No error messages.
-No third party codecs.
-Mercury playback: I believe so.
EDIT: I forgot to mention. My drives are laid out as such:
C: SSD 128GB (Premiere Pro installation)
D: 1TB HDD (250GB of cached conformed media)
F and G: External Drives with raw media
UPDATE: It appears to be, in part, reconforming my media? My Media Cache is growing in size slightly as the project loads, but no new media has been added since I last edited. It's gone from 235GB to 240GB, and it's loaded around 1/3 of the content at this point.