That was what caught my eye about MS's antivirus offerings from the start. I was really impressed how well it ran without me ever noticing.
I got a new laptop from work recently and I didn't spend a great deal of time looking it over as i was busy and ... of course I hit some random performance problems as McAfee was abusing my machine while I was trying to work. Endlessly installing antivirus programs is getting pretty old.
I had to help some regular computer user to clean their computer; one of the user's requests was to "fix" their McAfee, meaning, to update the subscription and solve other "security threats" (not viruses) that McAfee reported. After seeing how indecent this antivirus is, how it uses real intimidation, and is very intrusive with constant pop-ups, we settled on not continuing the subscription and getting rid of it altogether.
I was dealing with MySQL running on a Windows server box with McAfee Active Response running (MarService.exe). It has a feature for tracking files created/deleted, which is accomplished by hashing all new files, saving them to its own local DB, and presumably pushing them to the management server async. The app running on MySQL frequently creates many new tables and fills them as part of SOP, so the disk was constantly hammered by both MySQL and McAfee...
I disagree that this incentive differs for Windows Defender vs other AVs.
All AV software has the desire to not negatively impact performance because if it's horribly slow people will uninstall it / quit paying for it.
The parent comment is pointing out that companies which primarily produce AV products benefit from the continued existence and fear of malware (to a degree at least). This is different for MS, as the eradication of Windows viruses will help Windows, which should be large enough a benefit to override any perverse incentives Windows Defender would otherwise have.
I know what you're trying to say is "also, Windows Defender isn't as slow", which happens to be true, but I think that's simply an emergent effect of other factors, such as AV companies feeling the need to "do more" to add value (whereas Windows Defender is funded by MS, so it has less incentive to "stand out").
I got a new laptop from work recently and I didn't spend a great deal of time looking it over as i was busy and ... of course I hit some random performance problems as McAfee was abusing my machine while I was trying to work. Endlessly installing antivirus programs is getting pretty old.