# What the memory gauge in NotchStar shows > The memory ring in NotchStar counts active, wired and compressed memory against your Mac's total RAM. Cached files are not counted. Canonical: https://www.notchstar.com/help/memory-gauge-in-notchstar/ Last updated: 2026-11-04 Published 2026-11-04. The memory ring in NotchStar shows active, wired and compressed memory as a share of your Mac's total memory. It does not count cached files, which macOS fills spare memory with and gives back when an app needs it. ## What goes into the number Each second NotchStar reads three counters from macOS and multiplies them by the memory page size: - **Active** memory, which apps are using now or used very recently. - **Wired** memory. Apple describes this as memory the system needs to operate, which cannot be cached or compressed. - **Compressed** memory. Apple says macOS compresses memory to free up RAM as the Mac nears its memory limit. The total is divided by your Mac's installed memory and capped at 100 percent. Cached files are left out on purpose, so a Mac that has simply been on for days does not look full. ## Colours The ring turns orange above 65 percent and red above 85 percent. ## Why it may differ from Activity Monitor Activity Monitor has its own Memory Used figure, and it also shows a Memory Pressure graph that Apple says depends on free memory, swap rate, wired memory and file cached memory. The two numbers can disagree because they add different things up. Use the ring for a glance and Activity Monitor when you need the detail. [A comparison of the two](https://www.notchstar.com/help/notchstar-system-stats-vs-activity-monitor/) lists what each one shows. For the full tool, read the [System stats feature page](https://www.notchstar.com/features/system-stats/). If the CPU ring is the one you want, read [what the CPU gauge shows](https://www.notchstar.com/help/cpu-usage-gauge-in-notchstar/). ## Quick answers. ### Why does my Mac use so much memory with nothing open? macOS keeps files in spare memory to speed things up, and Apple calls these Cached Files. NotchStar does not count them, but Activity Monitor lists them separately, so check there if the number looks high. ### Is a high memory ring a problem? Not on its own. Pressure matters more than the percentage. Activity Monitor's Memory Pressure graph is the better guide to whether your Mac is struggling. ## 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. - [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. - [NotchStar System tab vs Activity Monitor](https://www.notchstar.com/help/notchstar-system-stats-vs-activity-monitor/): NotchStar gives five readings at a glance. Activity Monitor gives per process detail. What each shows, and when to open which. - [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. ## 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 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. - [Does NotchStar system stats drain your battery?](https://www.notchstar.com/help/does-notchstar-system-stats-drain-battery/): The System tab reads a few counters once a second and only while it is open. No battery cost has been measured, so none is claimed.