A 4-hour render that sleeps at hour 3
You start a long export in Final Cut Pro, queue up a batch in Handbrake, or kick off a Blender render that's going to eat the rest of your afternoon. Leave the room. Three hours in, Mac decides you're idle and goes to sleep. Render stops.
Some apps can pick up where they left off. Others can't. Even the ones that resume have to re-initialize the GPU and rebuild their pipeline, which adds time and sometimes introduces artifacts.
You'd think rendering apps would tell macOS to stay awake. Compressor usually does. But Final Cut, DaVinci Resolve, Blender, Handbrake? Not always. If the app doesn't explicitly say "I'm busy," the idle timer keeps ticking and your Mac sleeps on schedule.
CPU threshold: auto-detect when you're rendering
Shake It On has a condition: "Only Shake If CPU usage above threshold." Set it to 20-30% and it activates automatically whenever your Mac is doing heavy work. Encode pinning the CPU at 85%? Shaking is on. Render finishes and CPU drops to 3%? Shaking stops. Mac sleeps normally.
You don't have to remember to turn anything on before a render or off after. The CPU threshold handles it.
20-30% is the sweet spot for most renders. Video encodes and 3D work push well above 50%. Normal background stuff (email, browsing, Spotlight) rarely sustains above 15-20%. No false triggers.
Pairing conditions for overnight renders
Starting a render before heading out for the day? Couple of extra conditions worth enabling:
- Paused When on battery. If you're rendering on a MacBook, you're plugged in. But if someone trips over the power cable, you don't want Shake It On keeping the Mac awake at 100% CPU on battery. It'd be dead in no time.
- Allow display to sleep. Overnight render doesn't need the screen on. Let it go dark while the system keeps working.
CPU threshold + battery pause + display sleep. Mac stays awake during the render, screen goes dark, everything returns to normal when the job finishes.