The Performance HUD
The HUD shows how the game is running, in a corner of the screen. It has five detail levels:
| Level | Shows |
|---|---|
| 1 FPS | Frames per second |
| 2 Frame time | Plus the frame time and a small graph |
| 3 Performance | Plus the 1% low, frame rate limit and refresh rate, CPU and GPU load |
| 4 System | Plus memory, temperatures, power, battery and the Mac's thermal state |
| 5 Diagnostics | Plus per-core load, clocks, how the frame is drawn, and the game's own memory use |
It starts off. Shift+F12 steps through the levels in a game (for that session), and the full overlay's HUD section sets the level and corner and remembers them.
Settings › Performance shows a preview of every level over your own game art: pick the Detail level the HUD starts at, the HUD corner and the HUD edge. Read temperatures and power uses macOS interfaces Apple doesn't document; turn it off and the HUD shows the Mac's thermal state (Nominal, Fair, Serious, Critical) instead. A game's Performance overlay setting shows the HUD from the start in that game.