Parental Advisor and Internet bandwidth problems

I've detected that if I activate the "parental advisor" tool, the bandwidth with any browser goes down from 300Mbps to 40-60Mbps. If I use an FTP or TORRENT client, I don't see this bandwidth reduction. I've tested two different PCs and Windows 10 and the problem is the same. When I disable parental control, the browser bandwidth recovers.