You open Task Manager and see svchost.exe running under the NetworkService account consuming 25% or more of your CPU. One CPU core is pegged at 100% while the rest of the system stays mostly idle. This behavior means a service hosted by the Service Host process is stuck in a loop or handling excessive network traffic.
The svchost NetworkService container runs core Windows services such as DNS Client, DHCP Client, and Network Location Awareness. When one of these services encounters a corrupted cache, a misconfigured adapter, or a network timeout loop, it can spin a single CPU core indefinitely. This article explains the three most common causes and provides step-by-step fixes to stop the CPU spike without reinstalling Windows.
You will learn how to identify the offending service using Resource Monitor, clear the DNS cache, reset network stacks, and disable problematic background services. Each method targets a different root cause so you can resolve the issue in under ten minutes.