A couple questions for you: Are you running Windows or Mac? How many processors? How much RAM? How many drives do you have attached to your system? What kind of work do you do? What kind of footage files are you working with?
I think that the only reason for moving these folders from their defaults would be to increase performance. When you render, are your CPUs working near maximum load? Is your memory usage maxed out? If either of these is the case, your disks are not a bottleneck and it doesn’t matter where you store files. If your RAM and CPU usages are low during render, then redistributing your files and getting faster drives may help.
Personally, Image Cache doesn’t do me much good, because I never use standard preview (spacebar). It’s not realtime, and it doesn’t include audio, so I don’t use it. I always use RAM preview (0 on the numeric keypad) or shift-RAM preview (Shift key and 0 on the numeric keypad; it functions the same as regular RAM preview, but you can specify different settings to trade off between speed and quality).
I don’t think where the project file is located impacts performance; it’s not accessed much except during opens and saves.
I don’t have much personal experience with Conformed Media Cache, because I always use intraframe-compressed footage to improve AE’s rendering speed and reliability. The only items in my cache are PEK files (audio waveform previews) and a few CAF files (conformed audio files), so I don’t think I’d see much benefit from relocating this folder.
Take a peek in your cache folder; if there’s a lot of video, you might relocate it to a footage drive, but again, disk speed may not be your rendering bottleneck.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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