After years of complaints about Windows Task Manager displaying CPU utilization incorrectly, a fix is finally on its way
We have put this to the test to figure out how inaccurate the previous Task Manager was by running 3DMark's CPU Profile test ...
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Microsoft releases update to make Windows Task Manager's CPU usage more accurate
In addition, if you intentionally lower the operating clock frequency to stabilize operation ( underclocking), the task manager would not display '100%' even if the actual CPU usage reached 100%.