CS5 multiprocessing on a 12-core Mac Pro

[Walter Soyka]

[Steven Nichols] “Hi have a 12-core Mac Pro and After Effects CS5. Since my Qio is not yet 64-bit compatible I had to boot in 32-bit. Then I unplugged the Qio and restarted in 64-bit.”

AE CS5 requires a 64-bit operating system (which gives it access to RAM above 4 GB), but it doesn’t require the kernel to be running in 64-bit mode.

[Steven Nichols] “But since then I don’t see any difference when the multiprocessor option is checked in AE prefs. Even more: it is faster when it is not checked!”

How much RAM do you have? What effects are you trying to render?

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]

AE CS5 requires a 64-bit operating system (which gives it access to RAM above 4 GB), but it doesn’t require the kernel to be running in 64-bit mode.
Well that’s good news! So that’s why I don’t see any difference with a 32-bit and 64-bit kernel.

How much RAM do you have? What effects are you trying to render?
48 GB.
I rendered a bunch a projects (Brian Maffit’s bench, some particular, some basic text and blur…)
I don’t get it: why is MP rendering slower ?

[Walter Soyka]

[Steven Nichols] “I don’t get it: why is MP rendering slower?””

It shouldn’t be. You’ve got plenty of RAM, so that’s not the issue. What preferences have you set under Memory & Multiprocessing?

Some specific effects temporarily disable multiprocessing, so if you’re using one of them, you should expect to see a performance hit.

OpenGL rendering also disables multiprocessing; if you’ve got that turned on, you should turn it off.

You should install the 10.0.1 update if you haven’t already.

If nothing else works, perhaps you might also try restoring the default preferences. It’s like trashing the prefs in FCP; just hold down Cmd-Opt-Shift while launching AE and it will reset them for you.

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 all of those but none worked.
I did a 20 sec test comp with just a moving text with a animated gaussian blur.
Rendering times are:
– 1min14sec with MP enabled (actual CPU: 20- RAM per CPU: 2 GB) The render bar seems to slow down every 10 sec or so, then goes again, ect.
– 34 secs without MP enabled
It does not make any sense!

[Steven Nichols]

Do you set MP in the Memory & Multiprocessing prefs only… or is there anything else ? Besides what are the best settings ?

[Walter Soyka]

Are you leaving any processors available for other applications?

From Memory (RAM) usage in 64-bit After Effects:

In many cases, performance is improved by using fewer than the maximum number of processors for Render Multiple Frames Simultaneously multiprocessing, even when you have enough RAM for all of the processors. After Effects is a multithreaded application that can also use other forms of multiprocessing beyond just Render Multiple Frames Simultaneously multiprocessing, and it is possible for the processors to become “overscheduled” if these threads are competing for the same resources as the background processes used for rendering with Render Multiple Frames Simultaneously multiprocessing. Therefore, the best approach is to begin by using a small number of processors for Render Multiple Frames Simultaneously multiprocessing; and then increase the number of processors used until you find the optimum number for your computer system and compositions.

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]

OK I’ll try that. But could you explain me why I see 24 installed CPUs when I only have a 12-core machine ?

[Walter Soyka]

[Steven Nichols] “OK I’ll try that. But could you explain me why I see 24 installed CPUs when I only have a 12-core machine ?”

Intel has a technology called hyperthreading which allows each physical core to present itself to the system as two virtual cores.

If you’ve got AE set to use all 24 cores, try backing it down to 20.

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

[Walter Soyka]

[Dave LaRonde] “Since AE’s multiprocessing mode can use up to 4 GB per core if set to its maximum, you could be trying to use 96 GB RAM! That’s a bunch of trouble.”

The 4GB limit is the old 32-bit memory address limit. With 64-bit addressing, the theoretical limit is absurdly high (I’ll regret this quote in 20 years) — 16 billion GB of RAM.

Technically, any one instance of After Effects would be able to access all the RAM in your system.

Practically speaking, I’d still target 2-4 GB per core.

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

[Walter Soyka]

[Dave LaRonde] “Now you’re making me feel bad that my new machine will have a mere 24GB.”

When I bought my current workstation a couple years ago, I loaded it up with 32GB of RAM, and the memory cost more than the rest of the computer.

What computer are you getting for home?

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