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13" MacBook Pro M1 + Studio Display XDR standby power draw seems crazy high?

V

v654321

macrumors member
Original poster
Hi all,

I recently put my desk setup on a smart plug with a power meter and noticed something weird with my M1 MacBook Pro and Studio Display.

When the laptop goes to sleep and the screen turns off, the smart plug shows a steady draw of around 46W. If I unplug the Thunderbolt cable from the Mac, the display's consumption immediately drops down to a normal 8W standby, which still is fairly high for a turned off display, but still acceptable giving its A13 SOC inside.

I've been digging into the macOS pmset logs and it looks like the Mac is triggering DarkWake events every 15 minutes for background maintenance (Spotlight/AI indexing and widget refreshes, among other things), which seems to be keeping the Studio Display's internal hardware awake.

Before I dump a massive wall of log details here, I wanted to check if anyone else has actually measured their setup's standby draw with a power meter? Are you guys seeing similar numbers when your Mac is supposed to be sleeping, or does your setup actually drop down to a low baseline?

If you want to see the most recent Wake/DarkWake events, you can copy/paste the following commands in a terminal:

pmset -g log | grep -e "Wake" -e "DarkWake" | tail -n 20

I'm fine with some level of power consumption during sleep if it means faster wake from sleep and up-to-date Spotlight results, but an almost continuous 46W for hours and days on end seems quite excessive.

Would love to get your input.
 
charging accounts for a chunk of it — the Studio Display is USB-PD'ing your MBP even during sleep, and macOS keeps the display's internal SOC (USB hub + Ethernet + camera + speakers) powered during DarkWake so the peripheral chain doesn't drop. two things dropped my sleep draw noticeably: sudo pmset -a powernap 0 and sudo pmset -a tcpkeepalive 0 — the latter kills the every-15-min wake pattern you're seeing in the log, tradeoff being Wake-for-Network-Access (breaks iMessage relay, Find My push, WoL). sudo pmset -a standbydelay 300 will also push into deep sleep faster.
 
Apologies for the delay in responding, but I've been trying to further troubleshoot/figure out what's going on.

I did eventually connect only the display in a smart plug:
  • The display indeed consumes only 1W in full standby mode without anything connected to it. My earlier 8W number was higher due to the parasitic power draw of other idle adapters, which have now been removed.
  • Once I connected my laptop, it charged to 80% and during active use the smart plug reported roughly 56W for the display + MBP.
  • After some idle time it went in sleep mode where both the display and MBP consumed roughly 44W.
  • I tried powering the MBP via the original charger while having the display connected over Thunderbolt but there was no change. Apparently macOS prioritises AC power from the display since it can deliver more Wattage.
  • I tried disabling the 80% charge limit since I thought it was trickle charging, keeping the display and MBP in a weird power state but no difference in behaviour.
  • The days before my post I also disabled tcpkeepalive and other pmset settings, nothing really changed.
Unless I'm missing something, I can’t believe one has to jump through lots of hoops to bring standby power consumption down to reasonable levels when connecting a modern Mac to a recent Apple Studio Display. I’ve been looking online and apparently lots of people encounter this high standby power consumption, both with modern Mac Mini’s and MacBook Pro’s, with virtually no software or configuration fix, aside from hoping Apple will eventually recognise that this wastes a lot of electricity and decides to fixes it in firmware.

Apparently the only reasonable alternative is by disconnecting the Thunderbolt cable, using a smart plug with some level of manual or automatic control, or indeed bringing it in a deep sleep state, causing the entire memory to be written to the SSD upon sleep, unnecessarily using up SSD write cycles.

A quick screenshot from my smart plug with some context added:

1782912067407.png

  • Before 08:00: ASD XDR without anything connected, consumption ~1W
  • 08:30: MBP connected, charged to 80%, general use and eventually idle for over 10 minutes, consumption eventually settles to ~56W after charge to 80% completed
  • 09:35: MBP goes in system standby, consumption ~43W
  • 10:00: General use of MBP, consumption ~56W
  • 11:00: MBP goes in system standby, consumption ~43W
  • 12:35: MBP disconnected from ASD, consumption ~1W
  • 13:18: Thunderbolt cable connected, MBP still in system standby but not doing anything on laptop, keyboard or mouse (all wireless), consumption 3W with occasional small spikes
  • 14:23: No use of any device but macOS decides the deep sleep is over and goes back to 43W, while system appears in system standby
  • 15:08: I awake my MBP to start typing this post
Truly puzzled. When my MBP is not connected to the ASD, it all works wonderfully, stays in a sleep state for hours on end, only sipping energy, as the way it should be. But once you have an ASD connected, the entire SOC in the ASD stays awake, consuming energy without being used. Disconnect the MBP and the ASD goes back to a full sleep state, also as the way it should.

I would really appreciate if others can measure the power consumption in sleep mode, regardless of the type of (Apple Silicon?) Mac that is connected to an ASD.
 
Totally different setup, but to give you the numbers …
Mac mini M4 with ASD 2022 measured separately.
Sleep mode ASD (black screen) fans NOT running 0,3x watt
Mac mini sleep NO background task running 0,5 watt

If the ASD 2022 fans kick in (during background task of the Mac mini) ASD takes 11.x watt

Different bug but FYI since macOS 15.4 my (and all other users with this setup) ASD fans keep running after the first background task. So there is no real sleep mode for the ASD 2022 since more than a year.
 
So, just to keep everybody updated, I think I fixed it:

1783926243791.png

  • Before 08:30: ASD XDR without anything connected, consumption ~1W
  • 08:30: MBP connected, charged to 80%, general use and eventually idle for over 10 minutes, consumption eventually settles to ~56W after charge to 80% completed
  • 10:00: MBP goes in system standby, consumption ~3W
  • 10:50: General use of MBP, consumption ~56W
  • 11:40: MBP goes in system standby, consumption ~3W
  • 12:00: General use of MBP, consumption ~56W
  • 13:30: MBP goes in system standby, consumption ~3W
  • 20:40: MBP disconnected from ASD XDR, consumption ~1W
I waited with posting this until I had about a week of this behaviour, and with both manually locking/sleeping the laptop, or letting it automatically go to sleep. It all works. The occasional spikes during sleep time are fine with me.

What did I do? Nothing fancy, aside from disabling powernap and tcpkeepalive. These are my settings:

1783927281594.png
1783927147662.png


Code: 
$ pmset -g
System-wide power settings:
 SleepDisabled          0
Currently in use:
 standby              1
 Sleep On Power Button 1
 SleepServices        0
 hibernatefile        /var/vm/sleepimage
 powernap             0
 networkoversleep     0
 disksleep            10
 sleep                1 (sleep prevented by bluetoothd, powerd)
 hibernatemode        3
 ttyskeepawake        1
 displaysleep         20
 tcpkeepalive         0
 lowpowermode         0
 womp                 0

Would love to hear of anybody with the same/similar problem, whether or not these settings fixed it for them as well. I'm not sure whether it's the same problem as people have reported where the ASD fans keep running during standby.
 
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