Download CPUSetter

CPUSetter adjusts the number of active cores in your cpu(s). It can also enable/disable hyperthreading on supported cpus.

To do this requires administrator access to the machine and a small privileged helper program is installed when you first execute CPUSetter.
A convenient link to the system Activity Monitor is provided so you can observe the impact of changes.
Authentication with your administrator credentials is required to make changes to your system.

The Processes window allows you to change the priority (nice value) of your processes, and to also limit the maximum CPU usage of any of your processes. You cannot adjust processes that do not belong to you.

Be aware that you may severely impact the operation of your system by adjusting these parameters.

Why would you ever want to do this?
  • Because you can!
  • Some software is licensed based on the number of active CPUs in the machine. CPUSetter will enable you to be within the terms of your software license.
  • Power Saving.
  • Disabling Hyperthreading can help mitigate Spectre/Meltdown expoits.
  • CPU resources can be allocated according to your particular workflow.
  • Probably other reasons too, just I can't think of them

The Handbrake process has been limited to a maximum of 100% CPU usage (i.e. 1 whole core from the 4 available) and also reniced to a priority of 19. It is constrained as can be seen by it requesting more CPU resource than it is allowed to use.

Download CPUSetter 1.4.5 (MacosX 10.10 and later)

CPUSetter 1.4.5 - Changes and Features


  • Fixed excessive CPU usage on waking from deep sleep.

Download CPUSetter 1.4.4 (MacosX 10.10 and later)

CPUSetter 1.4.4 - Changes and Features


  • Updated Preferences window controller.
  • Added documentation and Help button.


  • Action Menu items were not being properly enabled.
  • Limiter/Adjustment controlls moved to PID Preferences.
  • Fixed compatibility issues with macOS 10.10 (Yosemite).

Download CPUSetter 1.4.3 (MacosX 10.10 and later)

CPUSetter 1.4.3 - Changes and Features


  • Fixed 'limited' application freezing in the background.


  • Cache Application icons for improved performance.
  • Actual CPU usage of a limited process is closer to the nominal value.
  • Added (optional) PID controller for CPU limiting.
  • CPULimiter cannot be killed or adjusted from within itself.


  • Processes window is restored to its previous location.
  • Fixed compatibility issue with macOS 10.12 (Sierra).

Download CPUSetter 1.4.1 (MacosX 10.10 and later)

CPUSetter 1.4.1 - Changes and Features


  • CPUSetter is notarized by Apple.
  • Context menu added to rows in Processes table. Right/Control click a row to see the menu.
  • Save/Restore 'reniced' processes.
  • Stop CPUSetter from sleeping when it is limiting processes.
  • Added authorisation control to bottom of Processes Window.
  • Action menu item to Show/Hide processes from other users.


  • No bugs reported.

Download CPUSetter 1.4.0 (MacosX 10.10 and later)

CPUSetter 1.4.0 - Changes and Features


  • Compiled with Xcode 10, Swift 4.2.
  • New window for CPU limiting and renicing processes.
  • New Preferences pane.


  • No bugs reported.

Download CPUSetter 1.3.2 (MacosX 10.10 and later)

CPUSetter 1.3.2 - Changes and Features
  • Added option for Launch at Login.

Download CPUSetter 1.3.1 (MacosX 10.10 and later)

CPUSetter 1.3.1 - Changes and Features
  • Hide the Hyper Threading control if not supported by the hardware. (e.g. intel i5)

Download CPUSetter 1.3.0 (MacosX 10.10 and later)

CPUSetter 1.3.0 - Changes and Features
  • Updated to Swift 4.

Download CPUSetter 1.2.0 (MacosX 10.10 and later)

CPUSetter 1.2.0 - Changes and Features
  • Rewritten in Swift.
  • Future updates via Sparkle framework.

Download CPUSetter 1.1.0 (MacosX 10.8 and later)

Download CPUSetter 1.1.0 MacosX 10.7(Lion)

CPUSetter 1.1.0 - Changes and Features
  • Window layout modified
  • Restore window to previous location at startup
  • Preference setting to restore configuration at startup or after system sleep
  • Preference setting to record configuration changes via Notification

Download CPUSetter 1.0.0

CPUSetter 1.0.0 - Changes and Features
  • First public release