Apple’s new M1 Macs use the same ‘always-on’ processor technology that mobile devices have been using for years. It has always been imperative that a mobile phone must be permanently sitting and listening, waiting for a call or message to come in, so it can sound the ringtone. Modern tablets such as the iPad evolved from this line of thinking and so are naturally always-on too.
Laptops and Desktops have however have never taken this route. Recent versions of Windows and macOS will wake up periodically to perform certain tasks, or in response network events, but I’ve never noticed them doing much in realtime.
I was surprised then to notice that my new M1 MacBook, while apparently asleep, was busy running rules on incoming mail seconds after it had arrived. My phone buzzes as a new email is received, and I open the mail app on my phone to see the message has been flagged, moved or whatever else I have set as a rule on my Mac. This would happen with my old 2013 MacBook, but the rules would only run every few hours. It’s not a bug as far as I can tell, as the battery life when the MacBook is sleeping is still outstanding. I’m yet to explore how this works, or how much 3rd party developers can take advantage of this always-on state, but the possibility of having powerful devices, which aren’t locked down in the same way as iPads and iPhones, performing useful tasks in near realtime while using hardly any battery, is pretty exciting.
Update: As of macOS 11.3, Apple has restored hibernation support to M1 Macs. Hibernation mode is a lower power state Mac laptops go into after being asleep for around 3 hours. I’ve not noticed any difference in behaviour yet, let me know about your experience in the comments.