I have an older server workstation with 12 cores (2x AMD Opteron hex-core 2.6GHz), 32 GB RAM, and a Sapphire HD6950 video card with 6x 2TB hard drives on SATA/SAS (motherboard has room for 12 drives). Despite not being a modern set-up, this computer has been fine with my previous projects of 4 camera angles at 1080/4K for live concerts 2+ hours long. As long as I don't edit with full effects on, I have never had to resort to proxies or any other tweaks.
My current project is using 8 cameras at 1080 (with one at 4K) for a 2.5 hour concert. I have had to create proxies (480, H.264) and yet editing is still unbearably slow. First I split the proxies up between 4 drives (2 per drive), but that actually seemed to make editing almost impossible. Then I consolidated all the proxies on to one drive, and I was able to edit, but had ridiculously long wait periods as the media cached. Load time can be five or more minutes when moving across the timeline, though I can actually multi-cam in real-time with this set up. I noticed Premiere never got above 11GB of RAM usage, so I thought I could move my 16GB of proxy files on to a RAM Disk, and leave 16 GB of system RAM for Premiere. This has had mixed results.
On the one hand, editing section by section is fluid and real time with zero effects on right now. On the other hand, once I get through about five minutes of timeline, the video goes blank or shows the "Media Processing" screen and I have a wait time of several minutes before the next "cache" is loaded, or whatever it is doing to process the film. My question is, is there a way to convince Premiere that my proxy files are already in RAM, or is there another way to load the hard drive versions of the proxies in to RAM so that Premiere accesses them instantly and fluidly? I don't know the process going on behind the scenes, but it seems exponentially counter-intuitive that I can handle 4 files at full resolution natively but can not handle 8 considerably reduced file versions located completely in memory.
(To clarify, this lag occurs both when viewing the multi-cam editor with 8 cameras playing back simultaneously, and with multi-cam editor turned off, showing only the single selected camera in the editor.)