As you learn more about how operating systems work, you may find yourself curious about what is happening just before your system fully drops into sleep mode. With that in mind, today’s SuperUser Q&A post has the answer to a curious reader’s question.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

The Question

SuperUser reader Ydob Emos wants to know what Windows 10 writes to a drive before going to sleep:

I have noticed that my Windows 10 laptop takes around six seconds to go to sleep, during which the SSD’s activity LED is on. I imagine that Windows is writing something to the SSD before going to sleep.

I remember my Linux systems going to sleep instantly when I pressed the sleep button, which makes me wonder if I can do the same with Windows 10.

Given that Hybrid Sleep is disabled, what does Windows 10 do with my drive before going to sleep and is it necessary?

What does Windows 10 write to a drive before going to sleep?

The Answer

SuperUser contributor DavidPostill has the answer for us:

I imagine that Windows is writing something to the SSD before going to sleep.

That is correct. If there is any data waiting in the disk’s write cache, it must be written to the disk before the disk is powered off. Note that disk caching can be disabled so that everything is written to the disk immediately. This ensures that data is not lost as a result of a power failure, but it does reduce performance.

Turn Disk Write Caching On or Off:

  1. Right-click My Computer, then click Properties.
  2. Click the Hardware tab, then click Device Manager.
  3. Expand Disk Drives.
  4. Right-click the drive on which you want to turn disk write caching on or off, then click Properties.
  5. Click the Policies tab.
  6. Click to select or clear the Enable write caching on the disk check box as appropriate.
  7. Click OK.

Source: How To: Manually Turn Disk Write Caching On or Off [Microsoft]

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

Image Credit: Device Manager Screenshot – DavidPostill (SuperUser)

Akemi Iwaya
Akemi Iwaya has been part of the How-To Geek/LifeSavvy Media team since 2009. She has previously written under the pen name "Asian Angel" and was a Lifehacker intern before joining How-To Geek/LifeSavvy Media. She has been quoted as an authoritative source by ZDNet Worldwide.
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