A new public beta version of App Tamer 3.0 is available! The most visible change in recent builds is the ability to display the amount of RAM used by each process. To turn it on, Control-click in the stats area at the top of the window and select “Show Memory Usage”.

Note that the numbers can vary from what you see in Activity Monitor because App Tamer totals up the memory used by any sub-processes and helper apps that are employed by an app or process. It does the same with CPU usage. So the numbers you see for Safari, for example, are the sum of the memory and CPU used by Safari and all of its helper processes (Safari Networking, Safari Web Content, PluginLibraryService, etc). App Tamer will show you a list of these sub-processes if you Control-click on an app and choose “Process Details…” from the contextual menu.

But Wait, There’s More!

So what’s more exciting than that? Well, while adding the ability to collect memory information, I reexamined App Tamer’s process monitoring more generally. I revamped its CPU sampling code, making it more accurate and more efficient. And I eliminated some “slop” in the process throttling engine, allowing it to better control really CPU-hungry processes. Long story short, App Tamer is now much better at controlling CPU usage, keeping it very close to the limit you set rather than bouncing around the target value.

There are also UI improvements to make it easier to see the current temperature on the graph and a clearer indication of how processes are sorted in the process list. Organization of the options in the Stats pane of the Settings window is more logical, and a message at the bottom of the main window explains why Auto-Stop is paused when it’s inactive for some reason.

Share Your Hopes and Dreams (and Bugs)

This is a beta release, so I really want to hear from you if you’ve found a bug, or if you have suggestions or other feedback. Send an email to AppTamer@stclairsoft.com.

Download links and a full list of changes in the beta are available on the App Tamer Testing Page.

I’ve been working on App Tamer 3 for quite a while, beefing up its internals to make it more robust and more efficient, while adding requested features and improving the user interface. It’s finally ready for public testing – I’m excited to hear what you think!

To get a copy of the beta, go to the Beta Testing Page.

If You’re New to App Tamer

App Tamer displays and controls how apps and services are using your Mac’s processors. There are hundreds of separate processes at work on your Mac – some very apparent, like Safari, and some that run in the background to support apps and the operating system.

All of these processes need processing (CPU) time to do their jobs, and macOS typically manages them fairly efficiently. However, it doesn’t always prioritize those jobs optimally. Spotlight, Time Machine, or a browser running in the background may use processing power that could be otherwise allocated to a task that’s more important to you.

App Tamer lets you take charge of processes that are consuming CPU cycles, slowing them down so they don’t impact your work as much. It can also shift processes to slower, more power-efficient processor cores, ultimately saving power (and battery runtime, if you’re using a MacBook).

And yes, if you’ve encountered a bug in macOS that inexplicably drives a service to use 100% or more of a CPU core, App Tamer can throttle that back to whatever CPU usage you decide to give it. Is photoanalysisd churning away on your Photos library to the detriment of all else? Set App Tamer to run it on the efficiency cores and give it no more that 10%.

New Features and Improvements

Here’s a quick run-down of the major changes in App Tamer. There’s lots more, but these are the highlights.

CPU Temperature

App Tamer now displays CPU temperature so you can see how CPU load is affecting temperature. This lets you make intelligent decisions about which processes need to be slowed down to keep your Mac cool and running quietly. And yes, you can automate app management based on temperature with custom rules (below).

CPU Usage Graphs with More Detail and Accuracy

App Tamer 2’s graphing of CPU usage was pretty rudimentary. Version 3 displays usage data more accurately with customizable colors, automatic scaling and properly annotated axes. It gives you more insight into what’s happening on your Mac.

Switchable Profiles

App Tamer’s ability to fine-tune priorities for apps and background processes is great, but up until now you could only set up one configuration of CPU limits, auto-hide, auto-quit, etc. Now you can create different settings profiles and switch between them. This lets you customize how apps are managed to fit different needs and workflows.

Custom Rules and Focus Filter

You can now set rules to switch between different settings profiles based on a number of criteria. Do you want to throttle CPU-hungry processes when you’re actively working in Final Cut Pro, but let them run when you’re using other apps? Slow down an app when the CPU temperature goes above 70°C? Automatically hide browsers when you’re busy writing? You can do that and more.

And if you use macOS Focus modes, App Tamer includes a focus filter that lets you switch to a particular settings profile when you enter a Focus mode.

All App Settings in One Place

You can browse and modify all customized app settings in App Tamer’s Settings window, making it much easier to review and change how you’re managing each application.

UI and Feature Improvements

I know it’s a cliché, but there are too many to mention. The UI works more smoothly, is translucent and better organized (but no, it’s not been rewritten in Swift UI – App Tamer needs to be compatible with very old systems and has to work consistently across all of them). The contextual menu in the process list offers process details plus web search if you want to know more about a process. You can throttle background processes like menu bar apps. High-CPU warnings are smarter. And a ton of other stuff.

Check out the Beta Testing Page for the long list of changes and fixes.

Under the Hood Improvements

App Tamer’s process monitoring and control engine has been revamped, making it both more efficient and more robust under high CPU loads (because you’re trying to manage your maxed-out Mac, right?). It’s also compatible with the new M5 CPU architecture in the latest Macs, and manages multi-process apps like web browsers and the Spotlight indexer more effectively.

I’ve come up with a solution to an annoying issue in App Tamer. When you throttle the CPU usage of apps, their attempts to play audio can result in the sound stuttering or cutting out if they’re getting too few CPU cycles. In some cases, this can even affect the sound played by other apps.

Version 2.8 of App Tamer adds a new checkbox to an app’s settings: “Don’t stop or slow when sound is playing”. App Tamer detects when there’s audio playing and runs those apps at full speed until the audio stops. This lets you throttle a web browser to 2% CPU when it’s in the background, but if you’re playing a YouTube video and put it in the background, the video will continue playing normally instead of (possibly) slowing down and stuttering.

So far this works very well – at the expense of letting those apps use more CPU while sound is playing, of course – but I’d like to get more feedback before officially releasing it.

The biggest issue is that there seems to be a bug in Monterey, Ventura and Sonoma that prevents apps from determining whether sound is playing when playback is going through AirPods or other Bluetooth devices. I’ve worked around the problem so it correctly handles all the devices I have here, but I’d really like to have more testing done with other system configurations and devices.

So – it’d be really helpful if you would:

1. Download the beta build of App Tamer and launch it.
2. Check the settings for the web browser you’re using – the “when sound is playing” checkbox should be turned on by default.
3. Play some audio. You’ll see a little speaker next to the app in the process list (see the image over there → ).
4. Make sure this works with a number of different audio output devices. Use your Mac’s speakers, your AirPods, AirPlay devices, Bluetooth speakers – whatever you’ve got.
5. Shoot me an email at AppTamer@stclairsoft.com and let me know what version of macOS you’re using and what works and what doesn’t. Hopefully there aren’t any reports in the latter category 🙂

Thank you!