German tests show: Many Mac virus scanners slow down a system

Malware also attacks Macs, even though such viruses are much rarer than for Windows PCs, so having a virus scanner operating on an Apple computer makes sense. But users should be aware that most protection programmes drastically slow down Macs, according to findings by the AV Test Institute in Germany. The group tested 13 security packages - three of them freeware - in October and November using Mac OS X 10.11 (El Capitan).
The best freeware solution in the test was Anti-Virus 9.4.0 from Sophos, which detected 100 per cent of the threats and slowed the system by only 20 per cent. The top paid products were BitDefender Antivirus for Mac and Symantec Norton Security.