Memory used
Climbs to the ceiling on every Mac and stays there. Alarming to read, and almost never useful.
macOS menu bar · Apple silicon · free
See it coming, before your Mac starts to stutter.
Memory pressure moves before your Mac does, and macOS keeps it three clicks deep in Activity Monitor. MemPressure puts it in the menu bar next to CPU, swap, compression and temperatures, drawn as bars, sparklines, numbers, or a cog that spins with your load.
pressure 28%
Live, not a screenshot. Drawn with the app's own geometry. Sized against the system icons, close to how it looks in your bar.
Why pressure
Built for a MacBook Air with too much open.
We run several projects at once on MacBooks, often with graphics work in the mix, and an Air has no fan noise to warn you that things are getting tight. Memory pressure is the first thing that moves. Watch it climb and you can close a browser window or quit something heavy while the machine is still fluid, instead of finding out once everything has started to stutter.
Memory used will not tell you this. macOS fills spare RAM on purpose, because caching is free performance, so a healthy Mac sits near the ceiling all day. Pressure tracks whether the system is actually struggling to keep up.
Memory pressure
Rises before the machine starts to stutter, which is the moment you can still do something about it.
Swap and compression
The mechanics behind the reading, listed on their own, so you can see why it moved.
Six ways to read it
Every metric, drawn the way you want it.
Pick a display style for each metric, not one for the whole app. Set the spacing, leave the colour off, and it sits in the bar like it shipped with the system.
Colour
Quiet by default. Colour when you ask.
Everything above is monochrome, because a menu bar you notice all day is a menu bar you end up hiding. Switch colour on in the settings and each widget shifts as its metric climbs, so a red cog means something instead of being decoration.
What it watches
Nine readings, one strip of menu bar.
Show the ones you care about and hide the rest. Click the bar to open the panel for the full set, the history and the settings.
Memory pressureStraight from the kernel, the same source Activity Monitor reads.
Memory usedApp memory, wired and compressed, matched to Activity Monitor.
CompressedHow much RAM the compressor is holding back right now.
SwapFlags when it approaches the size of your physical RAM.
CPUTotal load, sampled on your schedule.
Per-core CPUEvery core on its own, with P and E clusters separated.
Chip temperatureRead from the built-in sensors. No kernel extension.
SSD temperatureThe drive sensor most tools never show you.
Battery temperatureWorth a look before you shut the lid on a hot machine.
How it is built
Written for the menu bar, not ported to it.
Native Swift
AppKit and Core Animation, with no web view and no cross-platform runtime. That is the download. Installed it takes 3.7 MB, three of which are the Sparkle updater.
Menu bar discipline
Widgets are drawn to the pixel at menu bar size, with spacing tuned to the rhythm of the system's own icons, so nothing sits crooked next to them.
Signed updates
Updates arrive through Sparkle and are signature checked before they install. It checks for new versions. Nothing else leaves your Mac.