Default macOS sleep modes

Continuing the discussion from Disk not ejected properly:

… Which begs the question: are these options still important?

For instance, the “put hard disks to sleep when possible” was important when you were using hard drives. Even a modern laptop HDD can consume about 10W when idle, so spinning it down when not used can save real power.

But does that matter when you are using an SSD? How much power does an idle SSD consume? Is it at all significant?

Likewise, when putting the whole system to sleep. How much power does a modern Mac consume when it is idle (that is, no apps actively doing anything)?

I assume putting the computer to sleep would prevent background tasks from running, but again, how much power does that consume? And if you are using power nap, does that undo the potential saving?

I would, however, definitely agree with putting the display to sleep when the system is idle, because backlights (even LED-based ones) do consume significant power. As do OLED screens, if they’re not showing very dark images.

Not a lot. Just checked the UPS in our office that has 2 M1 iMacs, 8 port switch, and Eero running off it. The iMacs are not asleep but the display is turned off. Power draw is about 0.4 amps so 48 watts. That’s why I don’t put the computers to sleep.

If anybody wants an easy way to measure power usage I recommend a Kill-a-watt P3 meter.

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That’s not negligible though – it’s like leaving an incandescent light bulb on 24hrs/day, which most people wouldn’t do.

Bygones. On Sonoma you’re essentially left with the option to sleep the Mac once the display is asleep (if you’re on AC power) or not.

One third of that is the networking gear then 2 iMacs which may use more power than a MacBook. One Mac running idle wouldn’t draw more than 15-20 watts which is similar to a lot of night lights people use. My electric cost to keep my iMac running 24/7 all year is less than $15 based on the amortized cost of my solar system.

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