A few days ago, I installed USB stick that we knew being infected. MSE was able to spot unusual .exe files however that was that -it would only report those to see if they were malicious.
Having been deeply disappointed -I've been recommending MSE to people for a couple of years now- I checked aforemention sites above to see that MSE could score 2.5/6 when it comes to detection rates while BitDefender, KAV and a couple of others scored 4.5-5 about detection rates.
However, as gamers, that would not be our only concern. The system impact of such software is crucial in making the choice and seeing MSE and BitDefender both score 5.5/6, the obvious way to go was BitDefender.
I'm using the trial, it wouldn't hurt to pay a couple of bucks to an AV that would keep your system safe and secure.
ZoneAlarm Antivirus + Firewall is a free option that scores a lot better than MSE. Give it a try if you'd like to.
ZoneAlarm
Detection: 5.5
Repair: 5.5
Usability: 5
MSE
Detection: 2.5
Repair: 5.5
Usability: 5.5
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