A big version of the RunCat app icon with stop-frames from an animation of a small running cat at the bottom. 🄍

RunCat and the battery-impact of processor indicators

RunCat is a cute cat-themed desktop pet for macOS that lives in your top bar. The cat plays a constant running animation where the cat’s running speed represents how hard your Mac’s processor is working. It can be a useful heads-up if a background app or a web browser tab is consuming lots of system resources. However, the cat can itself be a problem for your battery life.

You can optionally add additional indicators next to the running cat for disk and network activity, and memory pressure. If you add more indicators, it becomes more information-overloading than cute, though.

The core concept with the running cat is a cute idea that makes me smile when I look up at it. But do you recall back in the day when the clock in the top bar used to blink the time-separator every second? or when the selected button used to have a pulsating ring around it? Apple disabled those features to reduce the Mac’s power consumption.

You’ve probably already seen where I’m going with this. The innocent little fluffer that’s running in your top bar is a continuous animation that causes battery drainage. Actually, the animation itself is fairly innocent. Modern Macs have better graphic stacks that don’t require repainting large sections of the screen to blink a time-separator. The application behavior still causes unwanted battery drainage.

This problem isn’t specific to RunCat. Any activity indicator like this (on any operating system) can help power-user feel more in charge of what’s happening on their computers. Quickly identifying misbehaving background apps or browser tabs can help you save battery life if you’re constantly glancing at the activity indicator and micro-manage your Mac. But the indicator itself is one of the types of background process you’d want to stop to help conserve power. For example, there are plenty of forum threads on the web discussing how to remove Adobe’s many persistent background processes. RunCat consumes more processor time in a week than Adobe’s much-discussed background processes.

You can use the Energy pane in the Activity Monitor app on your Mac to see the energy impact of applications over time. The energy impact value isn’t a percentage of your battery life or anything quite as specific as that. It’s a relative measure you can use to weigh apps against each other to see how they impact your battery life.

The cat-app receives a low energy impact value (0,8 on my Mac) compared to applications I’m actively using — like my browser and email apps. However, it’s rated higher than many utility apps that I interact with frequently throughout the day.

When I look more closely at the numbers, I can see that RunCat interrupts the processor four times every second. Processor interrupts prevent the processor from maintaining deeper power-saving modes when it would otherwise be idle. Remember the law of small numbers before you dismiss that number. Four times a second quickly accumulates to 2,4 million times per week. To bring that number into context, the Dock generates about 1 million interruptions in a week with normal use. The Dock is also doing a whole lot more than RunCat.

The running cat may be cute. But uninstall it if you appreciate longer battery life over a cute processor-activity indicator that you probably don’t need. Try setting a photo of a kitten as your desktop background image instead!