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Edit Prefs file & limit multiprocessors (eg use 6 cores not 8) ??
Is this safe?
From generalspcialist.com
Multiprocessing performance issues with multi-core machines, especially high-end 8-core hardware. When all 8 cores try to render a complex or memory intensive composition with Render Mutliple Frames Simultaneously, the application can become memory starved if each process has insufficient memory. To remedy this, there is a text preference to control the maximum number of cores that Render Multiple Frames Simultaneously will use. Open the text preference file and look in the [“MP”] section for:
“MaxNumberOfProcesses” = “0”
“0” is the default setting, which disables this preference setting. For better performance on an 8-core machine with 8GB RAM, for example, change the “0” setting to “4” and save the preference file and restart After Effects. This restricts multiprocessing with Render Multiple Frames Simultaneously to 4 cores, each getting approximately 2GB of RAM. -
4 Replies
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this was based on a technote from adobe, so it should be safe as long as you remember how to set it back if needed…
the original technote was for 8.0 and 8.0.1 when when it was noticed that 8+core machines had stability issues when rendering with multiprocessing enabled. in particular i think it was rendering large frame comps or complex comps… i believe the problem was fixed in 8.0.2.
i had made a suggestion that someone try this method to free up resources for other apps that they wanted to run simultaneously while ae rendered (fcp and dvd studio pro)… i think that the initial report was that it didn’t help, or didn’t help as much as they had hoped, this may have been due to the other software being multithreaded and pulling resources from all 8-cores regardless of the ae setting.
now there is the question of do you really need to do it…. if you are working with hd or larger frame sizes, then maybe. if you are working with sd, probably not. when you currently render a typical project, are you seeing the ram usage (in the render queue) hit you max ram cache setting (60% by default). if not you aren’t using all the ram you have, or have allotted to ae, so decreasing the number of processors available to increase the amount of ram available to fewer cores may not make sense. i’m currently use a 4-core mac pro with only 4gb of ram on mostly sd projects and i rarely ever hit my max ram cache setting, for what that’s worth…
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Kevin, many thanks for the response. I’ve recently upgraded from a 4 core to an 8 core with 10GB of RAM.
I’d been using Nucleo Pro but on the 8 core with Leopard it seems to make AFX CS3 unstable, AFX crashed several times a day until I removed Nucleo Pro entirely. Gridiron hasn’t responded to my posts yet so I’ve been looking for an alternative.
I now use Lloyd Alvarez’s BG render script which can invoke Multiprocessing but has no control over how many cores are employed for the render — an option available with Nucleo.
I’ve done the prefs edit and it seems to work: according to activity monitor 8 copies of aeselflink launch but only 4 gobble the available RAM.
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i’ve heard about several other people having problems with leopard and nucleo pro, i would expect to see an update/patch for nucleo soon. although it’s curious that they haven’t posted it as a known issue that they are working on…
but it’s a pretty cool adaptation of the hack to allow free up resources while running the background render script. how does ae work while the rendering in the background? i’m curious how render a preview worked while background rendering, since i assume the hack would effect the number of cores for preview rendering. but of course just being able to continue working without ram previews is still a nice advantage.
i may have to try it on my 4-core just to give myself one core to keep on working…
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
When it worked BG render with nucleo was seamless. You could continue to work in in After Effects with no noticeable performance hit, though RAM preview was out of the question. One great feature is Commit to disk.
I would highly recommend the product, download a trial an check it out.
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