Bitdefender, F-Secure, Kaspersky Rated Top Anti-Virus Suites

Here's some good news for PC users: If Windows is your operating system of choice, just about any of the best antivirus software will protect you from almost everything malefactors can throw your way, according to the latest results from the AV-TEST security institute.

AV-TEST, a security firm based in Madgeburg, Germany, subjected 28 security suites to a battery of exhaustive tests to determine which could best protect user PCs. Included in the running were major providers like Bitdefender, free services like AVG and the built-in Microsoft Windows Defender. (The lab also tests the best Mac antivirus software and the best Android antivirus apps.)

The first step in testing the suites was to expose them to 400 strains of brand-new, or "zero day," malware. The programs would have no prior knowledge of these threats, meaning they would have to rely on their detection algorithms to separate dangerous software from benign system files.

The second test measured each program's efficacy in detecting and removing 60,000 known pieces of malware. Instead of simply having a program scan a machine and erase all offending files, researchers gave each program a chance to exercise all of its security protocols to detect malware, including real-time monitoring.

Finally, AV-TEST measured each program's system demands and usability. Having a virus detection program that slows your computer to a crawl, AV-TEST argued, is a virus detection program hardly worth using. Likewise, not knowing how to access most of a program's features essentially renders it useless.

The top contenders

In the first test battery, three programs received 100 percent ratings across the board: Bitdefender, F-Secure and Kaspersky Lab. Those who use G Data, Symantec, BullGuard, Trend Micro, Avast, Microworld, AVG or ESET have little to worry about, though: their ratings range between 97 and 100 for both real-world detection and the reference tests.

Windows Defender scored considerably less well in the real-world trial, however: It detected only 79 percent of zero day malware programs, even though it succeeded in isolating 97 percent of known threats.

Bitdefender, F-Secure and Kaspersky Lab also tested extremely well in the practical categories, coming in first, fourth and second, respectively (Symantec came in third). Results were decidedly more mixed here, though: Some lightweight programs were not very intuitive, and some system hogs were as easy-to-use as software gets.

Once again, Microsoft Windows Defender came in almost at the bottom of the list, placing 14th out of 15. On a 6-point scale, AV-TEST gave the program an abysmal 1.0 on Protection, a decent 3.8 in System Load, although it earned a perfect 6.0 in Usability.

Based on AV-TEST's results (which took six months to fully perform and analyze), Microsoft's own software is woefully inadequate for protecting Windows PCs, but almost any other program — even the best free antivirus software — should do just fine.

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Marshall Honorof

Marshall Honorof is a senior editor for Tom's Guide, overseeing the site's coverage of gaming hardware and software. He comes from a science writing background, having studied paleomammalogy, biological anthropology, and the history of science and technology. After hours, you can find him practicing taekwondo or doing deep dives on classic sci-fi. 

  • ingtar33
    its been a while since windows defender was worth the time to install it. Rolling with avast! at the moment, long time AVG user, just got tired of all the ads on the new one. Nice to see the free ones are basically indistinguishable from the paid services still. That's also been the case for over a decade as well.
  • debido666
    Microsoft Security Essentials or Windows Defender?
  • the1kingbob
    I wondering the same thing. I have never used Windows Defender. I have always used Microsoft Security Essentials... It has done well for viruses, but doesn't seem to do well with malware.
  • compprob237
    Hmm, I've been more inclined to trust the testing done by Matousec myself. Their testing puts the software through a range of protection requirements.

    Most notable is the common heavily advertised security solutions, Norton IS and McAfee, show up well down on the list at only 9% and 3% protection respectively. Kaspersky gets a great score (86%), BitDefender gets a bed score (7%), and F-Secure gets an awful score (3%).

    It's interesting that Comodo Internet Security Premium is at the top of the list... and is Free.
  • mauller07
    i would not touch bitdefender again with a barge pole, had nothing but system slowdowns and random bsods when it was on my pc.
  • 016ive
    I wonder why Comodo isn't on the list?
  • smeghead4269
    @debido666 & the1kingbob: Windows Defender is basically the equivalent of Microsoft Security Essentials for Windows 8...even though Defender was originally the name of an anti-spyware program for Windows XP/Vista/7 that was superseded by MSE. I have no idea why they decided to recycle the Defender name instead of just sticking with MSE. Then again, this is the same company that put the number ONE in the name of their THIRD game console. The people who handle the naming of products at Microsoft have clearly been smoking something.
  • clivene09
    BitDefender should never EVER be considered a top antivirus software. About three and a half years ago, everyone running windows 7 64 bit had all their .dll files quarantined as a virus after an update. Once things went wacky, if you decided to try and restart your computer, windows would fail to load at all because all the .dlls were in quarantine. F BitDefender.
  • DjEaZy
    Kaspersky 4TW!!!
  • Vorador2
    I've been using Avira for a while. It's not the best (it tends to give false positives for any application that uses code injection techniques, not only malicious applications) but it's very lightweight.

    In my work we use Kaspersky AV 6. It works well, but it slows down the system to a crawl.