Watch your Apple Silicon Mac's live power draw

One of the underappreciated joys of Apple Silicon is how visible its power draw is — these chips swing from sub-watt idle to tens of watts under load very quickly, and watching that number is honestly a good way to understand what your Mac is actually doing. macOS hides it, but the data is plentiful if you know where to look.

How to read live power

powermetrics

The canonical tool.

1. Open Terminal.
2. Run sudo powermetrics --samplers cpu_power,gpu_power,ane_power -i 1000.
3. You'll get per-second readings for CPU package power, GPU power, and Neural Engine power.
4. Ctrl-C to stop.

Key lines to watch:

• CPU Power — total wattage drawn by the CPU complex (P-cores + E-cores).
• GPU Power — wattage drawn by the integrated GPU.
• ANE Power — Neural Engine wattage. Nonzero means an ML workload is running locally.
• Combined Power (CPU + GPU + ANE) — useful “all silicon” number.

On a MacBook Air with no fans, total package power around 10-15W is the sustainable cap. On a 14”/16” MacBook Pro with Pro/Max chips, you’ll see 30-90W under load depending on chip variant.

asitop (third-party, recommended)

If you want a friendlier live view: pip install asitop, then sudo asitop. It’s a curses-based dashboard built specifically for Apple Silicon — wattage, frequency, residency, all in one screen. Open source, popular among the M-series performance crowd.

A menu bar readout

For ambient awareness, a menu-bar power readout is the right place — it’s the number that tells you “the chip is working” without staring at percentages. Beacon includes live power draw alongside its other readouts.

1. Install Beacon.
2. Click the Beacon icon and check the detail panel for current CPU and GPU power draw.
3. Combined with the temperature readout, you get a clear picture of how hard the chip is working and how much heat it's making.

What you’ll see

A few patterns once you watch this regularly:

• A web browser scrolling a heavy page: 5-12W (mostly GPU and one P-core).
• A Zoom call: 8-15W (camera processing on the ANE plus GPU).
• A Swift project build: 25-60W on Pro/Max, often pinning all P-cores.
• A local LLM running on the GPU: most of your power budget; chip will get hot.
• “Idle” with Mail and Safari open: 1-3W. Apple Silicon at rest is remarkably frugal.

Once you see the numbers, battery life starts making sense — “my MacBook does 15 hours” is just “average draw is 3W and the battery is 50Wh.” Visibility is the cheapest way to learn the chip.