I have read through the archives. I see this has been an existing problem for years. I have tried the fixes, turned off multiprocessing, etc.. switched to aurio to output on blackmajic output card, (Which also does not work well). And I an not udin compressed media, mainly audio and iamges. So it is not a mpeg issue.
I just migrated to a new machine. I went from Dual Quad Xeon circa 2007 to a brand new Dual Hexacore Xeon with Bigger Video Card, 32 gigs fast ram, SSD drives, the works.
Upon opening a project created on my old machine, I find it is now WAY slower to preview. I have the 10-30 seconds of "Locking existing frames issues" I also have the inability to create h.264 files which has been described as a dying support feature of Quicktime on x64 multiprocessor machines.
Back to the preview problem. This is HUGE. I paid quite a bit of money to upgrade my equipment, and now I am slower than I was on an 8 year old machine.
The archives document that Adobe has known about and has been workign on this for some time. It is useless to turn off audio. Client cannot approve without audio, I cannot time without audio,
Look, if the same software worked on machine A but not faster bigger machine B, I think it is a driver conflict/hardware conflict issue of some sort. It would be great if Adobe could figure this out soon, as I am feeling like one heck of a dope for spending alot of meny on a new machine, time to migrate all of my apps and plugins, and now I am slower than I was before.
What version of After Effects are you using? If CS6, make sure that you've installed the latest updates ( http://adobe.ly/lsrkmJ ). They fix a lot of problems.
Regarding H.264 in QuickTime, see the "QuickTime failure because of its inability to work with large number of processes" section on this page:
I used to find switching off audio preview stopped this for me obviously at the loss of audio in your ram previews.
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Chris Forrester - Compositor/Animator
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