Microsoft has shipped Windows 10 October 2018 Update with tons of new features, improvements and a broken Task Manager. As spotted by a Reddit user, the Task Manager tool is not reporting accurate CPU usage after upgrading to Windows 10 October 2018 Update.
Microsoft acknowledged the bug in Task Manager last month when it released the RTM Build 17763 to the Windows Insiders in the Fast and Slow Ring. Unfortunately, the known issue also exists in the public version of Windows 10 October 2018 Update as the Task Manager is reporting inaccurate CPU usage.
On Patch Tuesday (October 9), Microsoft is expected to ship a new cumulative update for Windows 10 October 2018 Update with a fix for the Task Manager bug and other issues.
Microsoft has tried to refine Task Manager in the Windows 10 October 2018 Update (version 1809). The Task Manager now shows you the power usage of each process on your Windows 10 device and there's another column called "Power Usage Trend" that shows you the longer-term trend.
Windows 10 version 1809 is gradually rolling out but you can manually download and install the October 2018 Update without waiting anymore. This is possible by checking for updates in Settings > Update & Security > Windows Update.