macOS CPU Monitor

rNitro

Real-time CPU usage, temperature, clock speed, and per-core breakdown. One command to install.

zsh — bash
# 1. Download the installer
~ %
# 2. Run it
⬇ Download install-rNitro.sh
What it monitors
📊
CPU Usage
Total load with a 60-second live history graph, color-coded by intensity.
🌡️
Temperature
Die temperature in °C with a visual gauge that goes orange and red under load.
Clock Speed
Base and boost MHz tracked live, showing how hard your chip is actually running.
🔲
Per-Core Breakdown
Individual usage bars and clock speeds for every logical core on your CPU.
How to install
1

Download the installer

Click the download button above to save install-rNitro.sh to your Downloads folder.

2

Open Terminal

Press ⌘ Space, type Terminal, hit Enter.

3

Run the command

Paste this and hit Enter. It compiles and launches automatically — takes ~30 seconds.

bash ~/Downloads/install-rNitro.sh
4

rNitro launches

The app installs to ~/Applications/rNitro.app and opens automatically.

rNitro v3.1.3

Shell installer · builds natively on your Mac · hardened install script

macOS 12+ Apple Silicon Xcode CLT required Free
SHA-256: e87270327b0adb0723a080e2e63e00ab44495a6c51aa0e88180bcfaaa7b7d595
This installer self-verifies its own checksum when run. To check manually before running it, see the note in the script's "Security: verify script integrity" comment.
⬇ Download installer
Changelog
v3.1.3
Refresh rate changed to 900ms. Added a ₿ symbol to the left of the menu bar CPU readout.
v3.1.2b
Stats now refresh every 500ms instead of every 1 second — the menu bar, popover, and game overlay HUD all feel noticeably snappier. The usage history graph buffer was doubled so it still spans a full 60 seconds at the new refresh rate.
v3.1.2
Menu bar now shows "CPU: X% Temp: Y°" instead of just a usage percentage, so both numbers are visible at a glance without opening the popover.
v3.1.1b
Patched major bug — a malformed edit had silently deleted the GraphView struct declaration, breaking the CPU usage history graph and causing the app to fail to compile. Fixed and verified.
v3.1.1a
Added an automatic update check. On every launch, rNitro checks rnitro.netlify.app for the latest published version; if a newer one exists, you'll see an alert and your default browser will open to this page so you can grab it.
v2.1.0
Added an in-game overlay HUD — like MSI Afterburner's on-screen display — showing live CPU%, GPU%, temperature, and RAM. Toggle with ⌥⇧O. It's click-through and stays on top of fullscreen games without stealing input. Also added "Launch App with FPS HUD," which runs a Metal-based game with Apple's own native Metal HUD enabled for real, engine-reported FPS and frame time — we don't fake FPS numbers, since macOS has no public API to hook another process's renderer. GPU usage and RAM usage are now read from real OS sources (IOKit accelerator stats, host VM statistics) too, not estimated.
v2.0.1a
Fixed minor temperature bug — the gauge could appear stuck at one value (e.g. 40°C) while in the Nominal thermal state. It now interpolates within each thermal-state band based on live CPU usage, so it moves smoothly instead of sitting flat. Still grounded in the OS's real Nominal/Fair/Serious/Critical signal, not a synthetic guess.
v2.0.1
Fixed menu bar bug — the menu bar popover's content was getting clipped/cut off. Version bump also marks the 2.0 line — real thermal-state monitoring and menu bar mode (introduced in 1.2.2) are now the baseline.
v1.2.2
Replaced the synthetic temperature estimate with a value driven by macOS's real thermal state (ProcessInfo.thermalState) instead of a fake formula based on load — still shown in °C for readability, banded by the OS's actual Nominal/Fair/Serious/Critical signal rather than guessed. Added menu bar mode: a live CPU% readout always visible in the menu bar, with a click-to-open quick view, independent of the main window.
v1.2.1
Patched minor bug. Added a custom app icon, generated programmatically at install time and embedded into the app bundle.
v1.1.0 — Security Update
Hardened the installer end-to-end: refuses to run via curl | bash, builds in a randomized, permission-locked temp directory instead of a predictable path under Downloads, verifies all required tools exist before use, checks the compiled binary isn't a symlink before installing it, refuses to delete ~/Applications/rNitro.app if it's been swapped for a symlink, tightens file permissions throughout, and ad-hoc code-signs the final app bundle. The self-verifying SHA-256 checksum is now pinned and published above.
v1.0 — Initial release
First public release. Native CPU usage, temperature, clock speed, and per-core monitoring, compiled locally via swiftc.
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