Extremely High CPU Usage - Service Host: DNS Client - Windows 10 Help Forums (2025)

My Windows Version: Version 1909 (OS Build 18363.535)

From time to time this process (in the title) will suddenly rise CPU usage, making everything extremely slow and even games from 1994 will play slowly, for example. Sometimes it subsides by itself, but sometimes I need to restart.

I'm at my wits end - I've search everywhere and all I can find are answers for previous OS or different processes that are hogging the CPU.

How do I fix this?

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Bump

I have the same or similar issue apparently, and it's rendered my laptop completely unusable. It started happening randomly this week after trying to install a windows update. The only solution I got was to restore to before the update, just a temporary fix.

This is absolute bullshit. I can't believe there's no solution for this.

I'll have to reinstall Windows 7 over the weekend

Yep. My restore point has version 1903 - which works fine. It's actually the same build number weirdly enough as 1909. From what I read somewhere, it's actually the same code package, with some extra features turned on. It also seems they changed their update delivery process somehow as well, it all seems a bit sketchy.
https://techcommunity.microsoft.com/...s/ba-p/1002660- - - Updated - - -

Feedback hub error report - who knows, maybe someone at MS will read it

Try Process Explorer that may give you more info, which is needed.

You should try some anti-malware scans, since it could be caused by an infection, like being part of a botnet.

Norton Rescue Tools
Online Virus Scan from ESET

You could try http://nirsoft.net/utils/live_tcp_udp_watch.html to monitor DNS requests.
Close all internet related software and watch if there are too many requests via port 53.

Slstar said:

How do I fix this?

Try this: Flush DNS Resolver Cache in Windows 10

You can also disable DNS Client, after you setup your DNS servers manually.

Change IPv4 and IPv6 DNS Server Address in Windows

Run CMD as admin and copy/paste to disable it, then restart.

Code:

reg add "HKLM\System\CurrentControlSet\Services\Dnscache" /v "Start" /t REG_DWORD /d "4" /f

To enable it back again: Run CMD as admin and copy/paste, then restart.

Code:

reg add "HKLM\System\CurrentControlSet\Services\Dnscache" /v "Start" /t REG_DWORD /d "2" /f

vgchat said:

[FONT="]Try [/FONT]Process Explorer[FONT="] that may give you more info, which is needed.[/FONT]

Thanks, I tried using the app but I'm not familiar with it so I wasn't able to find anything conclusive.

TairikuOkami said:

You should try some anti-malware scans, since it could be caused by an infection, like being part of a botnet.

Norton Rescue Tools
Online Virus Scan from ESET

I scanned with ESET Internet Security but I wasn't able to find anything.

TairikuOkami said:

You could try http://nirsoft.net/utils/live_tcp_udp_watch.html to monitor DNS requests.
Close all internet related software and watch if there are too many requests via port 53.

Yes, I used that app and there were like 12 request on Port 53.

TairikuOkami said:

Try this: Flush DNS Resolver Cache in Windows 10

I tried this but the process continued with its excessive CPU usage.

TairikuOkami said:

You can also disable DNS Client, after you setup your DNS servers manually.

Change IPv4 and IPv6 DNS Server Address in Windows

Run CMD as admin and copy/paste to disable it, then restart.

Code:

reg add "HKLM\System\CurrentControlSet\Services\Dnscache" /v "Start" /t REG_DWORD /d "4" /f

To enable it back again: Run CMD as admin and copy/paste, then restart.

Code:

reg add "HKLM\System\CurrentControlSet\Services\Dnscache" /v "Start" /t REG_DWORD /d "2" /f

THANK YOU!

This resolved the isue!

What kind of Network card do you have? I'm having the same issue on an insider build, but I've been messing with my Network Card drivers so I was wondering if it was related. I have Killer E2200 but I don't want to blame it yet.

opened this post while I was searching for the same issue and I also have the Killer e2200 card.
it's driving me crazy.

If you have a spare USB port and Wi-Fi access, you could always try a wireless dongle. Or if you're on a wired Ethernet, try something like the US$24 StarTech USB 3.0 to GbE Adapter I keep around just in case I need to use a different LAN connection on one of my PCs. That will quickly tell you if the problem is the NIC or something else.
FWIW, I've had my share of Killer NICs over the years, and have had occasional issues with some of them.
HTH,
--Ed--