Third-party lab tests reveal that both deliver acceptable but mediocre malware protection. Avast Free Antivirus: Antivirus performanceĪvast shares its malware-scanning technology with its sister company, AVG.

The Avast Online Security extensions for Chrome and Firefox block known malicious websites and web trackers and examine webmail attachments, but the extensions must be downloaded on their own. Avast Free Antivirus also scans USB flash drives for malware. Suspicious items are uploaded to Avast's lab for analysis, and new malware signatures are pushed out to Avast's 400 million users every few hours. Avast Free Antivirus: Antivirus protectionĪvast Free Antivirus' malware scanner compares files and programs to a database of known malware and looks for telltale signs of an infection. It includes unlimited versions of Avast's Cleanup, Passwords and SecureLine VPN programs, which would cost a total $130 if purchased separately. Avast's Ultimate program costs $100 yearly for a single PC.

Avast behavior shield is now off