Q100117: Limiting threads in Nuke with the -m flag



This article provides information on how you can limit the number of threads being used by Nuke.


By default Nuke uses all the threads of the CPU in order to run as fast as possible. However, in some circumstances, utilizing the maximum number of available threads can make Nuke unstable and cause crashes or slowness.
To isolate your issue as being related to multi-threading, please try launching Nuke with a limited number of threads and see if the problem is resolved by doing this.
Launching Nuke with fewer Threads
To run Nuke with fewer threads you must use the -m n flag when launching Nuke.
Substitute n by the number of threads you want to run Nuke with, so for example, if you wanted to run with three threads you would use -m 3
  • Please note that using a number greater than the amount of threads you have in your computer will not increase Nuke's performance.

Select a platform below to expand information on how to set the command line flag:

Windows: Open a Command Prompt window and run the following command:
"C:\Program Files\Nuke15.1v1\Nuke15.1.exe" -m 3

Open a Terminal window from Applications > Utilities and run the following command:
/Applications/Nuke15.1v1/Nuke15.1v1.app/Contents/MacOS/Nuke15.1 -m 3

NOTE: Prior to Nuke 12, the default command for macOS also included the v# for the application name (shown in bold below). For example:

/Applications/Nuke11.3v6/Nuke11.3v6.app/Contents/MacOS/Nuke11.3v6 -m 3

Open a terminal and run the command:
/usr/local/Nuke15.1v1/Nuke15.1 -m 3

NOTE: These instructions are based on having Nuke installed in the default location. If this is not the case then the commands will need to be modified accordingly to run from your custom installation location.

Additional Information
If using less threads helps with your Nuke issue then try increasing the number of threads you are allowing Nuke to use, until you notice the optimal performance. 

Please find more information on the command line flag for -m in our online documentation.

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