Large Premiere Pro CS6 Project running very slowly

Question

Hi there folks. I'm about to ask a question to which I'm fairly certain the answer is "You need to upgrade your RAM and Video Card." But I thought I'd toss the question out to Adobeland just for the slightest, minesculest chance there might be a software fix.
Basically, I have a huge project for this promo. About 4TB worth of footage all in all. Almost all of it is PRORES 4444 from an Alexa (which runs like a charm) but there's also a great deal of full hd XDCAM transcodes of several of a networks full feature films (They're about 80GB each).
These films are killing my project. I can't even watch them for more than a few seconds without Premiere just stalling out, that's fine, I can cope with that. But apparently just having them in the project is enough to slow the whole thing down even when I'm only using a few clips on my 60" timeline. It takes 45 minutes for the project to fully load up, and I'm constantly clearing the cache.
I'm running a Mac Pro (Mid 2010) 2 x 2.4Ghz Quad-core Intel Xeon, 12 GB 1066 Mhz DDR3, ATI Radeon HD 5770 1024MB using OSX Lion 10.7.5....
If there's any little software tweaks or fixes that can speed up Premiere.
PS - I've tried using project manager to create a new trimmed project with handles, but for some reason this never works for me. It just makes copies of the entire original clips without trimming them. I've also tried transcoding the Larger files to smaller versions, but this process is taking way too long and keeps crashing
Any advice would be greatly appreciated.
Much Love
Martin

Answer 1

In After Effects you 'purge' the cache to free up RAM, in order to preview other compositions. In Premiere, it is a bit different, because this program works with different cache files and different ways of storing them. There are files used for previews/renders, created by the user - and files for caching information about media used in the project (metadata, waveforms etc.), created by Premiere. The only ones you can delete are the render files, found in Adobe Premiere Pro Preview Files (if you don't need them at one point; they can be easily recreated by rendering again). All the others (the ones you say that you delete through 'Preferences') need to be kept, because Premiere works with them. I assume this is the reason it takes that long when opening the project, because Premiere needs to re-cache everytime. Don't delete them and see how it goes.
Just as a reference point for you: I have a powerful computer (dual Xeon, dual nVidia, 64GB RAM), and I still have to decrease the playback quality sometimes to 1/2. The lowest I can go is 1/4, and I assume your Premiere allows decreasing at least to 1/8, with the rest of values grayed/unselectable.
I think you need a better graphic card first, one that is accepted by Premiere, for its CUDA capabilities. Check their website, I think your Radeon is not allowing the use of Mercury Playback.
Best,
Mark