But if you worry about viruses and other attacks, you really should install and use your windows 10 computer in the way it is supposed to, just like a Linux or mac already is.. please check out: http://windowsguides.eu for more information...
"By always using the Admin-account you hinder important security-features from working as intended. In fact: Most computer-viruses REQUIRE you to be logged in as admin to successfully infect your computer, So NOT logging on as Admin actually protects you better, than your virusprotection does. This is why Mac and Linux are ALWAYS used with a limited account which, if necessary, can be temporarily promoted to "Admin". And this is also the reason why you should always have a separate admin account and use a normal user account yourself. (Even when you are the only one who uses the computer)."
EDIT: Those of you who rekommend crap like Defender and webroot should look at the 1:st picture in this link: Sophos ranks #1 for endpoint protection by SE Labs The RED parts shows how much the tested securitysolutions actually miss..
That says: The more red a "security"software has= the more compromised your computer will be,
And compromised means: where malware managed to fully infect and damage your computer..
As you all will see: The worst protection is given by malwarebytes, closedly followed by: WEBROOT..
You should NOT EVER use any of these even if you got payed to... Microsofts crap (Defender) also has a large red part.. that tells you that you WILL get infected if you keep using it..
NOTE! There is only one protection that has a entirely green line..
Please also check the: exploit protection link in the same article.. there wou will see that microsoft EVEN WITH EXPLOIT PROTECTION FAILS TO PROTECT AGAINST EXPLOITS IN 16 CASES OUT OF 35.. (without Exploit protection activated it fails in 23 cases out of 35) The tested one Is actually the same antivirus as Defender, but with functions for central management in corporate networks.
Microsoft Defender is just as underdeveloped as microsofts first Windows firewall was when released.. you know the only firewall in the world that only checked incomming traffic (totally ignoring outgoing traffic)..
When defender catches up with the real antiviruses, the real ones have already moved on to new technologies and new ways to detect and undo malware..
YMMV. Try free or trial versions of various antivirus software and see what's the lightest. You can probably find out when you go to file explorer and try to view folders with lots of files, including those in external HDs, run various programs, etc.
I use McAfee. I paid INR ₹800 for 3 computers and unlimited phones. I do not use it on phones since I don’t really think it is necessary. The protection is good. I have tried to open known unsafe files and it immediately detects it. False positives are also less. I guess it is fine for any system user.
McAfee offers OK protection, but has always been a system resource hog. I wouldn't wish McAfee on my worst enemy. Also having endpoint protection on a phone is a good idea. Phones have been a lucrative target for cyber crime and will continue to be so. There is more and more malware being released on Android and iOS everyday
I think the free ad-supported AVs are mostly resource hogs, and data miners. Plus the trend tends to be if one is using an ad-supported AV that you end up installing 1 or 2 more free "malware" scanners. So you end up having more resource hogs, start up ones too.
It's too bad that it's evolved into that model. I want to say that when the free to use AVs started coming out after ZoneAlarm Firewall free version really gained popularity. They offered pretty good basic protection and would lead to people purchasing the premium editions. I remember I used to use Panda AV's cloud scanner as a 2nd option and it was fast and worked well.
I wonder what happened to make this data mining model blow up...Facebook's model?
If you want lightweight antivirus for your system you can use the built-in Windows defender.
But it may not protect your system very well.
You could also try Avast or webroot.
Both these give average security and are lightweight.
Webroot is good. I used to use it. But why pay for the protection when you have it built-in with WD. And the OPs question was about the cheapest and lightweight AV and what's cheaper than free or more lightweight than what's already built-in in lieu of installing something extra?
I would never install Avast free or paid. It used to be trustworthy back in the day when we started to see a lot of freemium AVs come out and compete with each other for customers. However, data mining is where they make their money now.
Running multiple end point protection solutions is often detrimental to the systems performance. Cylance with WD are no difference. They will step on each other examining files and quarantining as well.
When Cylance installs it should register with the Windows Security Center and Windows Defender should not be running.
Also the Defense in Depth approach to security suggests running multiple DIFFERENT protection layers and not multiple same layer protections. What is Defense in Depth?