App Tamer from St. Claire Software

St. Claire software makes an app that can help control heat and fan noise, extend your battery time and increase the amount of CPU power available for you frontmost application. App Tamer comes preconfigured to automatically reduce the CPU and battery usage of Safari, Firefox, Google Chrome, Spotlight, Time Machine, Photoshop, Illustrator, Word and many other applications when they are idle. It's similar to the built in Mac feature called app nap. but app nap only works on hidden applications or applications whose windows are completely covered.

App Tamer takes advantage of the Apple silicon processors by transferring background apps to the efficiency cores while keeping active applications on the faster performance cores. You can let App Tamer run automatically or you can set your own parameters for specific apps. If App Tamer detects high CPU usage from an an app, you will be alerted and offered a chance to throttle it. This helps identify apps with bugs that cause excessive CPU use you may not be aware of.

App Tamer is available from the developer's website for $14.95 and it has a two week free trial.