# NotchStar System tab vs Activity Monitor

> NotchStar gives five readings at a glance. Activity Monitor gives per process detail. What each shows, and when to open which.

Canonical: https://www.notchstar.com/help/notchstar-system-stats-vs-activity-monitor/
Last updated: 2026-11-04

Published 2026-11-04.

NotchStar is not a replacement for Activity Monitor. The System tab gives five headline readings you can see in a second. Activity Monitor is the place to go when you need to know which process is responsible and why.

## What each one shows

| | NotchStar | Activity Monitor |
|---|---|---|
| CPU | Whole Mac, one ring | Per process, history graph, per core view |
| Memory | Active, wired and compressed against total | App Memory, Wired, Compressed, Cached Files, Memory Pressure graph |
| Disk | Used share of the startup volume | Reads and writes per process |
| Network | Download and upload speed, WiFi and Ethernet | Bytes sent and received, per process |
| Battery | Charge level and charging state | Energy impact per app |
| Open it | Hover over the notch | Spotlight or Applications, Utilities |

## What NotchStar adds for processes

The **Disk** tab has a **Monitor** section. Its Usage view lists the five busiest processes by CPU and the five using the most memory, refreshed every 3 seconds. It does not give history or per process network and energy.

Its Ports view lists programs listening on a TCP port, which Activity Monitor does not list. See [the Ports list columns](https://www.notchstar.com/help/notchstar-ports-list-columns/).

## Which to use

- A glance while you work: NotchStar. It is already in the notch.
- A fan is loud, or the Mac is slow, and you need a name: Activity Monitor, then NotchStar's Monitor for a quick check.
- A server is hogging a port: NotchStar's Ports view, which can [stop it](https://www.notchstar.com/help/stop-process-on-port-notchstar/).

Apple's page on memory in Activity Monitor explains the terms used in the table. For the NotchStar side, read the [System stats feature page](https://www.notchstar.com/features/system-stats/) and [what the memory gauge counts](https://www.notchstar.com/help/memory-gauge-in-notchstar/).

## Quick answers.

### Can NotchStar replace Activity Monitor?

No. It shows totals and a short list of the busiest processes. Activity Monitor has per process memory, energy, disk and network detail that NotchStar does not.

## Keep reading.

- [CPU, memory, disk, battery and network](https://www.notchstar.com/features/system-stats/): Live CPU, memory, disk, battery and network speed gauges in your Mac notch. Sampling only runs while the tab is open, so it stays light.
- [Disk space, duplicates, apps and cleanup](https://www.notchstar.com/features/disk/): See free space, find big folders, duplicates and app leftovers, compress media and clean caches from your Mac notch. Everything goes to the Trash.
- [What the memory gauge in NotchStar shows](https://www.notchstar.com/help/memory-gauge-in-notchstar/): The memory ring in NotchStar counts active, wired and compressed memory against your Mac's total RAM. Cached files are not counted.
- [What the CPU gauge in NotchStar shows](https://www.notchstar.com/help/cpu-usage-gauge-in-notchstar/): The CPU ring in the NotchStar System tab shows how busy your whole Mac is, as a percentage, sampled once a second while the tab is open.
- [How to stop a process on a port with NotchStar](https://www.notchstar.com/help/stop-process-on-port-notchstar/): Press Stop on a Ports row, then press it again to confirm. NotchStar sends SIGTERM, a polite quit request, and never forces a process.

## More in System stats.

- [What the CPU gauge in NotchStar shows](https://www.notchstar.com/help/cpu-usage-gauge-in-notchstar/): The CPU ring in the NotchStar System tab shows how busy your whole Mac is, as a percentage, sampled once a second while the tab is open.
- [What the memory gauge in NotchStar shows](https://www.notchstar.com/help/memory-gauge-in-notchstar/): The memory ring in NotchStar counts active, wired and compressed memory against your Mac's total RAM. Cached files are not counted.
- [What the disk gauge in NotchStar shows](https://www.notchstar.com/help/disk-gauge-in-notchstar/): The disk ring in the System tab shows how full your startup volume is, counting space macOS can reclaim as free, so it can differ from Terminal.
- [What the battery gauge in NotchStar shows](https://www.notchstar.com/help/battery-gauge-in-notchstar/): The battery ring shows charge level, turns green and reads Charging while plugged in, turns red under 20 percent. It does not show time remaining.
- [How NotchStar measures network speed](https://www.notchstar.com/help/network-speed-in-notchstar/): NotchStar shows download and upload speed in bytes per second from your WiFi and Ethernet interfaces, so VPN traffic is not counted twice.
- [How often NotchStar updates system stats](https://www.notchstar.com/help/how-often-notchstar-updates-system-stats/): The System tab samples once a second, and only while it is on screen. The Monitor section in Disk samples every 3 seconds, ports about every 9.