There are lots of studies[1] by various groups that say Windows defender is just as good and alternative AV is no longer needed. I also recall seeing that non Windows defender AV's cause significant performs problems although I can't find a reference.
Thanks. I downloaded Boreal on this recommendation and have paid the 99p premium upgrade because after trying a few clients it is far superior. Also after lurking for years long this is the first comment I’ve ever made!