Get Alerted if Mac Processes & System use too High CPU

When I recently decided to install the macOS 26 Tahoe beta, I remembered that previous beta versions had the side-effect of causing high CPU load by certain macOS tasks. And usually it’s already a bit late when you notice this only once the Fans kick in, then check the «Activity Monitor.app» to find the culprit.

After searching the web a bit, I found exactly the solution that I wished for: proactive Notification center alerts, if either an App, Process, or the overall System CPU usage reaches critical limits.

Set up a CPU process watcher running in the background of macOS

This simple yet powerful script was originally developed and published by vladzima on GitHub – but after trying it for a bit, I felt it needs some improvements, which I added to my Fork of the project:

^{Link to GitHub where the setup_cpu_monitor.sh bash-script can be downloaded}

chmod +x /path/to/setup_cpu_monitor.sh
./setup_cpu_monitor.sh

Good thresholds to use for CPU monitoring of your Mac ⚙️

Generally I prefer the following thresholds, following a bit common “rule of thumb” I’d say.

• Per-process threshold: remember that multi-threaded apps can easily exceed 100%
  → 0.25 x (#cores x 100)
• Overall system threshold: about 75–85% of max #cores
  → 0.85 × (#cores × 100)
• Check interval: focus on long-running high CPU, ignoring short-term spikes (“false-positives”)
  → 300 seconds (5 minutes)

Dummy CPU Stress Test for macOS 🧪

Naturally you want to test if the CPU monitor alerts work properly. There’s a free tool from the Mac App Store that is easily configurable for that: