Slow internet until I open Task Manager

This could sound very rare but is that, everything on my PC from opera GX to steam to discord get slow, pages take years to load, discord chats take years to load, tried change DNS and using The first 5 options of AV + malware bytes + roguekiller + hitmanpro. Also tried with safe Mode + Internet connections and well some malwares and Viruses was detecte but The problem remains… Do a speed test and get the usually 170-180 Mbps optic fiber but pages take time to load… Tried cleaning temps running tron etc… But no luck.

Also this problem get “temporally solved” when I open Task manager. But after a time it gets the same and task manager dont show me any mother program using The Ethernet connection… Any advice for this?.. Format is The easy way but not The only one… Just need to try The other ways.