Avast. Avira has better signatures, but the free version of antivirus is bloated with ads & protection mechanics are lacking (outdated) other antivirusesWhich one is best Avira or Avast ?
Avast is less resource hungry, has the agressive mode ( if enabled) . It has less ads than avira, and you can choose min settings when installing avast ( pop-ups can be disabled & offer ads when av gui opened are blockable with firewall)
Avast is privacy wide probably worse than avira, but avast is more commonly used nowadays than avira is.