AfterEffects

Render multiple frames simultaneously

After Effects can start additional processes of the After Effects application to run in the background to assist the main application with the rendering of frames for RAM previews or final output. These background processes have the name AfterFX.exe (Windows) or aeselflink (Mac OS).

Each background process renders its own frame and runs on a separate processor core (CPU). The number of processes used to render multiple frames simultaneously is never more than the number of processors. The number of background processes that can run on your computer also depends on the total amount of system RAM and the amount of RAM that is assigned to the main application (Maximum RAM Cache Size). The amount of RAM required for each background process varies depending on your system configuration; at least 1GB per process is recommended.

Note: You can check the current value for Maximum RAM Cache Size by choosing Edit > Preferences > Memory & Cache (Windows) or After Effects > Preferences > Memory & Cache (Mac OS).

If background processes are used for rendering, then the main foreground application is not also used for rendering. This means that creating background processes only adds to the total number of processes used for rendering if there are enough resources for at least two background processes to run.

  1. Choose Edit > Preferences > Multiprocessing (Windows) or After Effects > Preferences > Multiprocessing (Mac OS).
  2. Select Render Multiple Frames Simultaneously.

The bottom of the Preferences dialog box shows how many additional processors (in addition to the worst-case scenario of one processor) will be used at the current settings. To increase the number of background processes that can run, decrease Maximum RAM Cache Size or install more RAM.

Important: You may experience a small delay when the background processes start for the first time, when the first render operation occurs. Deselecting Render Multiple Frame Simultaneously stops the background processes; reselecting the option causes the same delay when the next render operation begins.

Because antivirus software operates by monitoring every read and write operation, such software can decrease rendering speed, especially with the Render Multiple Frames Simultaneously preference selected.

If the rendering of a single frame requires more RAM than is available to the individual background processes, then After Effects will not render multiple frames simultaneously and will instead use only the main foreground process to render all frames for that composition. If After Effects can’t use background processes to render multiple frames simultaneously, a message appears in the Info panel.

Note: After Effects can also use multiple processes to accelerate rendering of a single frame. This form of multiprocessing can take advantage of hyper-threading. The number of CPUs that After Effects reports in the Multiprocessing Preferences dialog box for accelerating rendering within a single frame counts the virtual (logical) CPUs available due to hyper-threading.