Current security products for Windows 8.1 put to the test. June 2015 https://www.av-test.org/en/antivirus/home-windows/windows-8/june-2015/ -------------- And the winner is: Microsoft Windows Defender 4.7 (Protection Score 0.5/6.0) .
Protection Score: 6.0 / 6.0 Performance Score: 6.0 / 6.0 Usability Score: 6.0 / 6.0 ------------------------- Avira Antivirus Pro 2015 Bitdefender IS 2015 Kaspersky IS 2015
Considering that almost all products did very well (Ahnlab is recently scoring tops in detection) one has an embarrassment of riches in selecting an AV... Maybe tests are getting too predictable or the bad guys decided to repent...