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Windows Defender can Significantly Impact Intel CPU Performance, We have the Fix
I no longer have issues with Windows Defender, but this might be helpful for some of you.
Kevin Glynn, aka "Uncle Webb," our associate software author behind popular utilities such as ThrottleStop and RealTemp, developed a new utility named Counter Control, which lets you monitor and log the performance counters of Intel Core processors since 2008 (Core "Nehalem"). During development for ThrottleStop, Kevin discovered a fascinating bug with Windows Defender, the built-in security software of Windows, which causes significantly higher performance impact on the processor than it should normally have. Of course a security software is bound to have some (small) performance impact during real-time protection, but this is much bigger.
The first sign that something is happening is that HWiNFO will be reporting a reduced "Effective Clock" speed when the CPU is fully loaded. A much bigger problem is that when Defender is affected by the bug, performance of your machine will be significantly reduced. For example, a Core i9-10850K running at 5.00 GHz all-core loses 1000 Cinebench points (or 6%). Such a performance loss has been reported by owners of Intel Core 8th, 9th, 10th and 11th Gen, both desktop and mobile CPUs, on both Windows 10 and Windows 11. AMD processors are not affected.
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Not having such troubles right now, but I sure have had some after upgrading machines to Windows 10 -- so thanks.
Incidentally, the solution advocated is a small utility called Counter Control
, now at v1.1 and downloadable at https://www.techpowerup.com/download/counter-control/
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Andrew, this is an awesome find and the solution is brilliant.
The issue goes back to the days when Windows Defender was introduced and was never fixed by Microsoft. It never fails; every time I start my day and get intense with my work, Windows Defender starts to scan, slowing down my PC. On each of my notebooks, I know it's running because I can hear the CPU fan running at top speed. I end up temporarily disabling real-time scanning and then I re-enable it when I can take a break from my work.
After my tests on two different notebooks, the tool/utility works perfectly. It addresses Defender's negative performance impact while the CPU fan slows back to a normal speed. At long last, I have a solution to a disruptive and irritating problem.
Thanks for sharing!