I'm an experienced Mac user but a n00b to Premiere Pro, and I have a question regarding my aging Mac Pro (1,1) running 10.7.5. It's currently equipped with a 5770 GPU (genuine Apple card, 1GB) and 8GB of system memory. There are oodles of diskspace free and my applications, scratch space, and video files are stored on physically unique, fast hard drives.
I recently decided to bail on the Final Cut world and try out editing in Creative Suite. I've always had Adobe apps for other things and as silly as this may sound, just never launched Premiere until now. I've mostly been editing in Final Cut Express, but got frustrated waiting for the 1080p support (which we all now know will never come as FCE is dead) and I'm not super thrilled by FCP X (at least not yet) so I decided to hop the fence and see what things might be like in the nirvana of "no, you don't need to fill disks with AIC and ProRes transcodes, you can just get to work."
I broke out my CS5 install media, set up Premiere Pro CS5, and quickly realized that it's CUDA only (no OpenCL, as far as I've read). Tried to throw some AVCHD clips from my camera on a sequence and just play them back, no effects or anything...terribly slow and stuttery (unusable). Okay, I think...maybe I'll try CS6 (after all it won Phillip Bloom away from Apple). I download the trial and install it, and try to do the same thing. Not much improvement, but then I notice that on startup that the Mercury Playback Engine is greyed out. Now I know the 5770 isn't an NVIDIA CUDA card, but it's not a complete slouch either. I was confused. Searched a bit and came up with all the suggestions to try deleting my opencl_supported_cards.txt file. I did so (well, I moved it out of the way).
CS6 then proceeds to launch with Mercury Playback Engine enabled! "AWESOME," I think to myself. Premiere launches in a fraction of the time it took before. I create a new project and a new sequence and drop in four clips that are 1080p60 and hit the spacebar...for the first two seconds or so the playback is gloriously smooth! Between this and how overall snappy CS6 feels now with Mercury enabled I'm on top of the world! Then it happens...after just two seconds or so, the playback starts juttering along again. It's not anywhere near as bad as before, or as bad as it was with CS5, but it's still not usable. In order to edit happily, I really want to be able to just throw footage around and preview it (before any effects) without rendering...otherwise for me the whole point of Premiere Pro is kind of lost and I could just be on Apple stuff waiting forever for my imports to always be transcoded (yuck).
My question is "does an original Mac Pro, with an upgraded 5770 GPU, have any hope of ever playing back AVCHD files at comfortable realtime speeds in Premiere Pro CS6, without rendering? Is there any amount of system memory one could add, or various tweaks one could do, to make this happen?"
I realize that my trusty Mac may finally be at the end of its useful life (it can't even run Mountain Lion without hacking it a bit). I'm excited that Apple may be releasing a complete revamp of the Mac Pro line this year, as I'm really in need of a new machine and would prefer to use OS X and not have to build a Hackintosh with a modern NVIDIA card inside to do it well. Thanks very much for your feedback everyone! I really appreciate the help. I need to know what my options are.