With regards to Defender being heavy. Aside from when opening folders with many files, another example is the CPU use when it scans a file that has just been downloaded. This often causes slowdowns on low end hardware.
i used MS Defender because it is better than Xcitium's AV because of Comodo's poor AV reputation. My current choice is Eset, replciing Xcitium and Defender.
It is enough without doubt, however MS who run the OS could & should not cause any slowdowns which is the reason I still don't use it despite this still being a pretty fast PC, MS IMO do not seem the best with most if not all of their Windows modules which explains why many don't use their search etc etc etc...To long to list them all.
Will Windows Defender be enough in 2025? I voted yes. I've used Kaspersky ESET and while they may be more comprehensive and certainly better, I've been quite sensible about the websites I browse lately, and I think Windows Security and Configure Defender are modestly sufficient.
Halp2001 Level X – Forum member who still believes antivirus isn’t a magic talisman
Defender in 2025 was like that student who finally scored straight A’s… but still drops their pencils in class. Yes, the tests made it shine, but false positives and slowdowns remind us it’s not flawless.
Here’s how I see it: combining Andy Ful’s tools with a free third‑party AV is like wearing both a belt and suspenders. Not because your pants are falling, but because you never know when you’ll have to run. And let’s not forget, 2025 just ended and 2026 has barely started—there’s not enough time yet to declare victory or bury paid AVs.
In the end, digital security doesn’t depend only on antivirus software. It depends on not inviting malware to dinner, on making sure your browser isn’t a revolving door for attacks, and on remembering that no program replaces common sense. Defender may be enough, but real defense starts with the user.