If you're only running Microsoft's in-built antivirus service, you might want to think again.
The latest antivirus scores from the Madgeburg, Germany-based testing lab AV-Test ranks Windows Defender as the worst-performing anti-malware app out of the 22 most common consumer products tested.
Windows Defender, baked into the latest versions of Windows, scored just 9.5 points out of a total of 18.
Breaking down that figure, the scores show the app protected against 89 percent of existing widespread malware threats, and 95 percent of new zero-day flaws. The app also scored a paltry score on performance, suggesting it hogs system resources, but scored top marks in user experience, indicating it is easy to use.
By comparison, ThreatTrack, which came second place Windows Defender, scored significantly higher with 12 points overall.
AV-Test measures products' protection against zero-day exploits, malware, and email and web threats, as well as usability and performance, which determine a final score in which the company ranks the products.
Avira, Bitdefender, and Kaspersky, all hit the maximum 18 score, ranking as the best antivirus services available.
McAfee, Norton, and Trend Micro products fell short of top points with scores of 17.5, a de facto joint second-place in the consumer rankings.