The Case for a Low Power Mode for Mac Laptops – and iPads

Marco Arment:

In light of today’s rumor that a Pro Mode may be coming that seems to offer benefits in the opposite direction, I wanted to re-make the case for a Low Power Mode on macOS — and explain why now is the time.

Modern hardware constantly pushes thermal and power limits, trying to strike a balance that minimizes noise and heat while maximizing performance and battery life. […] Apple’s customers don’t usually have control over these balances, and they’re usually fixed at design time with little opportunity to adapt to changing circumstances or customer priorities.

The sole exception, Low Power Mode on iOS, seems to be a huge hit: by offering a single toggle that chooses a different balance, people are able to greatly extend their battery life when they know they’ll need it.

Arment has some interesting numbers showing the difference on a new 16-inch MacBook Pro while running a third-party kernel extension that disables Intel’s “Turbo Mode”. You lose about 50 percent of performance but gain maybe an additional 50 percent of battery life — and your MacBook stays very cool. A lot of people in a lot of situations would happily make that trade-off, especially if it were as easy to toggle and as noninvasive as it is on iOS. When I use Low Power Mode on my iPhone, I’m hard-pressed to notice any difference other than the yellow battery icon, even though benchmarks suggest the CPU is throttled to about half speed. Apple’s A-series CPUs are so fast that half-speed is plenty fast.

The elephant in the room is the Mac’s transition to Apple-designed ARM processors — a transition we’ve all expected to come any year now for, well, quite a few years. Apple’s plan for extending MacBook battery life might just be to switch processor architectures and nothing else. Note too that iOS’s Low Power Mode is for iPhones only — iPads don’t have it. That bodes poorly for the odds of a Low Power Mode for MacBooks — it feels like a feature Apple believes is needed only for phones.

Now that I think about it, why doesn’t the iPad have Lower Power Mode? This could be a huge game changer in a “forgot to charge my iPad before a long flight or car trip” scenario. I just spent 15 minutes searching the web to make sure the iPad really doesn’t offer this feature, because it seems so bananas that it doesn’t.

★ Friday, 17 January 2020