Microsoft Defender is an excellent anti-virus and cybersecurity platform and wins plenty of plaudits as such. However, there are apparently downsides to running Microsoft Defender on your PC, and one of them may be performance compromises. According to TechPowerUp (TPU), there is a bug in Defender that specifically affects Intel CPUs and not AMD processors.

TPU’s research builds on an earlier report from AV-Comparatives in May. That first report showed how Microsoft Defender was amongst the worst anti-virus solutions for hogging system resources. TPU follows up by saying this is probably down to a bug in the service.

The outlet comes to the conclusion because it seems Defender’s system hogging only affects Intel processors and not AMD. TPU discovered the MsMpEng .exe file – the process for Microsoft Defender – chews through Intel CPU cycles.

This has a direct effect on the performance of devices running Intel processors. Interestingly, the earlier AV-Comparatives test was done on a machine running an Intel Core i3 CPU.

“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.”

Microsoft Defender Bug

TPU puts this issue down to a bug in Microsoft Defender that causes the suite to use more Intel Performance Counter Monitors (PCMs) than it needs. This then spreads to cause issues with other processes.

Microsoft has yet to issue a response to these claims or roll out a fix for the Defender bug.

Tip of the day: If you need to Create, Delete or Resize Partitions, Windows has everything you thanks to the built-in Disk Management-tool.