April 21st, 2025

The ongoing story of seconds on the taskbar

Over a decade ago, I noted that early beta versions of the taskbar clock showed seconds, and sometimes even blinked the colon like some clocks do, but it was removed because the blinking colon and updating time were ruining Windows 95’s benchmark numbers due to the need to keep all of the code paths related to text rendering in memory, as well as the stack of the thread in the Explorer process that updates the clock.

Even though computers are not under the same tight memory constraints as Windows 95, the taskbar still does not show seconds because Terminal Services would have hundreds of updating clocks, and even on single-user systems, the energy efficiency team gives the side-eye to any timer that runs faster than once per minute.

But finally, in 2023, the Taskbar added an option to show seconds. The option is however disabled by default, and it comes with the warning “(uses more power)”. How much power is it using?

The Taskbar team ran power consumption tests to try to convince the energy efficiency team that even though there was an extra cost, that extra cost was not exorbitant.

A member of the Taskbar team told me that their preliminary measurements showed that Explorer consumed 0.417 mW of energy in its default configuration, but the energy usage went up to 5.42 mW if seconds were enabled on the taskbar. This is over a factor of ten, so that sure seems like a big jump.

I’m having trouble finding information on how much energy a laptop screen consumes. This Web site gives a range of 200 mW to 1100 mW active power consumption for a 16-inch screen at 100 nits. Do I believe these numbers? No. Will I report them anyway? I guess I just did.

If we accept these numbers, then an additional 5 mW doesn’t seem quite so bad overall.¹ It’s an extra 2.5% on the high end, or 0.05% on the low end. That’s a loss of 3 to 15 minutes over a 10-hour period.

¹ The energy efficiency team looks at the system as a whole. I mean, sure, Explorer decreasing battery life by 15 minutes over a 10-hour period might not sound like much, but suppose 10 other components come to the same conclusion. Now you’ve lost over two hours. They also look at the aggregate impact of Windows on the global environment and make recommendations like having Windows Update perform its work when there are more low-carbon energy sources available. You can use the PowerGridForecast class to use this information in your own programs. There’s even sample code.

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Author

Raymond has been involved in the evolution of Windows for more than 30 years. In 2003, he began a Web site known as The Old New Thing which has grown in popularity far beyond his wildest imagination, a development which still gives him the heebie-jeebies. The Web site spawned a book, coincidentally also titled The Old New Thing (Addison Wesley 2007). He occasionally appears on the Windows Dev Docs Twitter account to tell stories which convey no useful information.

20 comments

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  • Igor Levicki 1 week ago · Edited

    @Danielix Klimax

    Replying like this because I can't reply to the post in question or quote it:

    > 1) What kind of memory metric are you using?

    Values for all svchost.exe as reported by tasklist memory usage column -- added up in Excel.

    > 2) Have you actually calculated amount of energy for those inactive services and keep on mind that there are several different refresh methods. And don’t forget to account for them being possible swapped out already.

    Did you read my previous post? I am not the one paid to do that.

    > 3) And still your complaint is pretty hilarious in light of...

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  • Ahmed Habub

    The energy efficiency team? Is that an april fools joke, or are they on permanent vacation?

    • ω

      On one hand, I get it. “Ha ha, Windows and efficiency?” And be sure to use a dollar sign whenever spelling ‘Microsoft’.

      On the other hand, I can’t imagine how one might miss all of the in-your-face energy efficiency UX surface area in Windows 11. I get the sense that’s the visible part of the iceberg.

  • Ron Parker

    PowerGridForecast looks really interesting, but I feel like it needs a way to override its data source. (Maybe it has one; I'll admit I haven't looked.)

    My local energy provider claims a fairly low emissions rate of .0406 metric tons of CO₂ per MWh, so it probably doesn't make much difference, but I also have a decent amount of solar generating capacity which makes that number somewhat lower for me, especially on sunny days. It'd be nice if Windows had some way to talk to my solar combiner so it could know when I'm actively backfeeding power into the grid, as...

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  • Dave Gzorple

    Of course that extra power use matters:

    Every mW is sacred,
    Every mW is great!
    If a mW gets wasted,
    Greta gets quite irate.

    (Nothing against GT, I just needed a name to use).

  • LB

    I still don't understand why having seconds in the calendar view only was a problem. In Windows 10 you could just click on the date to open the calendar view and it shows seconds there for as long as you need, then when you click away it hides again. That sounds like a very optimal situation for reducing power usage. So why was that removed in Windows 11? And why now are some people getting Windows 10 builds that remove it from Windows 10 as well? This forces people to either turn it on all the time or to keep...

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    • Christopher Lee

      Control Panel still has a built-in clock that updates the seconds in real-time. You can find it via (right-click the taskbar clock; Adjust date and time / Adjust date/time; Add clocks for different time zones / Additional clocks; Date and time tab).

      • GL

        @Bob Loblaw: This is one of the many cases when you don’t need to do the CLSID dance. Easier by just going to Control Panel, then Clock and Region, then context-menu “Date and Time” and choose “Create shortcut”.

      • Bob Loblaw · Edited

        (see GL’s solution above)
        For anyone interested, there’s a way to create a direct shortcut to the Date and Time control panel page.
        Search for explorer clsid guid shortcuts and you can find it.
        (apparently I’m not allowed to post the actual shortcut here – I added a comment yesterday that never got approved)

    • Joe Beans

      Exactly. Forced regression as if Google or Apple people were running Microsoft and humiliating its customers.

  • GL

    I’m still wondering how energy consumption compares between Windows 8.1 start screen and Windows 10 v22H2 StartMenuExperienceHost.exe. The 8/8.1 animations are just so much more crisp than 10/11. Did 8/8.1 use more power to be crisp, or did 10/11 use more power than necessary and slowed down rendering?

  • Brian Boorman

    Is nitpicker’s corner still a thing? Your first sentence should start “Over two decades ago…” as the linked post is from 2003.

  • Matthew van Eerde (^_^)Microsoft employee

    What if we showed just the tens digit of the seconds?

  • Igor Levicki · Edited

    @Raymond Chen:

    Members of the energy efficiency team should have a stern talking to with Windows developers who keep adding dozens of new background services to Windows -- when did they last check how much resources and power those use? At least with seconds on taskbar if the users ask for it then it's justified, nobody asked for all those dumb services which just serve to increase the malware attack surface anyway yet most of them are on by default even if Microsoft's own security guidelines say they should be disabled and 90% of users don't need many of them for...

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    • Yuhong Bao

      Part of the reasons why I wrote about CompatTelRunner is that it can affect old Windows 7 PCs booting from spinning rust.

    • raykoopa

      I also think that in times where computers have 16+ GB of RAM, we should bother about an operating system needing 200 MB more than the predecessor for absolutely no extra features. After all, unused / free RAM consumes no power, and simply paging stuff in from the hard drive is clearly more power efficient.

    • Raymond ChenMicrosoft employee Author

      Notice that the services consume 0% CPU when not in use. Some of them even shut themselves down when they haven’t been used for a while. Whereas seconds on the taskbar continues running all the time.

      • Danielix Klimax 2 weeks ago

        @Igor Levicki
        1) What kind of memory metric are you using?
        2) Have you actually calculated amount of energy for those inactive services and keep on mind that there are several different refresh methods. And don’t forget to account for them being possible swapped out already.
        3) And still your complaint is pretty hilarious in light of “modern” browsers…

      • alan robinson

        fair point – but where’s the careful cost/benefit analysis? So far I can’t see any improvements in Windows since Win 7 yet surely the amount of code included and presumably running is much larger in Win 8/10/11. Again, to be fair this is really an empirical question, but I think the odds are quite good that Win11 uses more power at idle or even when being used.

        Not to mention the much, much larger environmental cost of the forced hardware discarded when Win10 goes EOL.

      • Igor Levicki

        There are 63 instances of svchost.exe on my PC right now (and that's with many unnecessary services disabled mind you). For something that by your admission is doing nothing (and something consuming 0% CPU is doing nothing) they surely consume a lot of RAM (707 MB total) -- RAM which has to be powered on, clocked at high frequency, periodically refreshed so it doesn't lose contents (and much more often than once per second). And that's all without taking into account paging and the associated disk reads and writes, etc.

        So by all means, please try to convince me that all...

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