This morning, my Mac started to be very very slow on web, but mails, ssh & co were not affected. Later I noticed that https traffic was not affected.
A few checks later, I replaced the -default- "80,8080,3128" in Prefs/Web protection/Ports used by HTTP with "8080,3128". Instantly, my web browsers came back fast; I repaired the web
ESET Cyber Security 6.1.12.2
OS X 10.11.3
Latest versions of Chrome, Firefox and Safari
Hope you will fix this fast, since I am no longer protected.
Best regards
Lol Zimmerli
SysCo