It turns out that Windows Defender can affect the performance of Intel CPUs.
According to the overseas IT media Tech Powerup, there is a bug that Windows Defender lowers the performance of Intel CPUs. For Intel Core processors, the symptoms were found from 8th to 11th generation. AMD CPUs are not eligible.
The reason for the performance drop is that Windows Defender randomly uses the hardware performance counters of Intel Core processors. Normal system utilities use the counter in mode 3. However, Windows Defender is set to mode 2 and steals system resources.
When Cinebench R23 was run on the Core i9-10850K system where the problem occurred, it was confirmed to be 15,824 points, a decrease of regarding 1,000 points from the existing total score (16,813). This is a performance drop of regarding 6%.
It is known that the workaround for this problem is to either disable Windows Defender or run Defender in Mode 3 using ThrottleStop 9.5.
