CS5 multiprocessing on a 12-core Mac Pro

[Matthew Woods]

I find the Multiprocessing Prefs misleading. The caption “Actual CPUs that will be used” should instead read “Number of AE rendering instances”

When using the Multiprocessing settings, AE spawns multiple copies of itself in the background to render. These background render copies can themselves use multiprocessing. If you spawn too many of these, and they are all trying to use more than one processor, they can step on each other’s toes and slow things down.

I have an 8 core hyper-threaded mac pro.
I find it generally works best when I set the maximum ram allocation per CPU,
and restrict it to using no more than the number of real (not virtual) cores – 2.
In my case 6, in your case 10.

Even with these settings, I regularly see it maxing all CPUs when rendering.
Sometimes I only see 6 maxed, it depends on what I’m rendering.

I also use a really handy utility called iStat Menus:
https://bjango.com/apps/istatmenus/

It puts my processor usage bars up in the menu bar.

You should see a steady use of processors when rendering.
If you see your processor use is oscillating between full and zero,
your background processes are stepping on each other’s toes, and
you should reduce the number of processors you are telling AE to use.

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[Steven Nichols]

I have an 8 core hyper-threaded mac pro.
I find it generally works best when I set the maximum ram allocation per CPU,
and restrict it to using no more than the number of real (not virtual) cores – 2.
In my case 6, in your case 10.

I tried that and I don’t see any difference with or without MP!!

[Steven Nichols]

Some comps render as twice as fast without MP. This is ridiculous 🙁 I am wondering if I really need a 12-core!!

[Walter Soyka]

[Steven Nichols] “Some comps render as twice as fast without MP.”

What happens with your computer while you’re rendering? Have you downloaded iStats as Matthew suggested? (MenuMeters is another option.)

I’d be curious to hear about RAM usage, CPU usage, and paging activity during your render, with and without multiprocessing.

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
Creative Cow Forum Host: Live & Stage Events

[Steven Nichols]

I tried iStat. Very interesting: when “Render Multiple Frames Simultaneously” is not enabled, I can see that all the cores are working! After Effects uses as much as 800%. What does this mean ?
When”Render Multiple Frames Simultaneously” is enabled, the machine is sometimes unresponsive and stuck… Very weird.

[Elin Grome]

I like the logic – I shall store this for future use 🙂

It’s all the those pesky details :p

[Steven Nichols]

I think I figured it out. For some compatibility issues with my Sonnet Qio, the Mac was running in 32-bit mode-hence the random behavior (it was like sleeping during rendering).
I restarted the Mac in 64-bit and everything is fine now.

[Oskar Ziemba]

Hello,

my 2 cents on this topic would be to open the Activity Monitor and watch the swap-value. I fiddled around until swap wasn’t used.Because at first rendering is ok and then the renderrate plummets, thats when the Swap goes up.

I have a new Mac Pro 12-core, 32 GB of Ram and i write to a Raid0 disk.
So for now my settings are as follows:

– 16 GB(!!) of Ram for other Applications
– 2 cores for other applications
– 6 cores at 2 GB usage

It gave me the quickest Results (roundabout 4-5 Hours) for rendering a 60 Minute 1920*1080 HD comp with keylight,lots of masks, color-management to a tiff-sequence.

i found the comment by Will Lockwood in the Adobe Forums extremely helpful: https://forums.adobe.com/thread/734343

hope it helps!
Oskar