Top MacPro grinds to halt on simple stuff

[Walter Soyka]

[Jean Piche] “When I launch my render, the machine works fast enough for about ten minutes and then stupendously grinds down to calculating a frame once in a while and giving me a render time of 26 hours for this 5 minute simple project.”

Can you trace the point where it slows down to any new layers or effects coming in?

[Jean Piche] “According to ACtivity Monitor, the machine seems to spend most of its time idling with the disk scratching away at what sounds like paging.”

What’s the RAM usage look like in Activity Monitor? If you are in fact running out of RAM (which could happen, due to the caching for the time-based effects), you might benefit from the Secret Menu — though I always treat this as the tool of last resort.

Hold down the Shift key, and keep it down. Click After Effects > Preferences > General. Continue to hold the Shift key, and click on the list of preferences. You should see a “Secret” menu item. In there, you can disable layer caching, and choose a frame increment at which AE will automatically purge memory. You might start with a value like 30 frames, and decrease it if you still see the render hanging.

If your renders were working perfectly, you would see a big performance hit for mucking with these settings; however, since they are not, it may help. Don’t forget to reset them for your next project.

[Dave LaRonde] “My suggestion: cut back to 8 cores/3.5 GB each, or even 6 cores, 4GB each.”

Thanks for the kind words, Dave — and this is a great suggestion. Multiprocessing only CS4 uses physical cores, though it can see the virtual cores. CS5 will apparently support hyperthreading (virtual cores).

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
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[Jean Piche]

Thanks so much Dave and Walter.

I still need to do some more experimenting but it looks as though Dave marks a point with the virtual core business. Reducing the number of cores to 8 sped up the crunching by a huge amount and brought it back to where it should have been in the first place. That is the only thing I tried. Haven’t given the “secret menu” approach a try yet. But right now, I am at least getting some performance. Perhaps it would be worth a place in a FAQ of some kind about the virtual cores… Adobe is, as far as I can tell, silent on the issue.

Best!

jp