All 4 of my Firefox installations started sucking big time recently. Unbelievably poor performance loading pages, which was working super fast before. Never had such an issue, running on 4 different, high performance PCs and having same symptoms, where I have to wait for Facebooks posts to load for minute or so. Youtube stops playing in the middle of the video. In meantime if I try same pages on other browsers everything works fast AF. I'm on 1000Mbps connection at office and 500Mbps home. Noticed massive increase in RAM usage, which used to be around 3GB, it is now using 6+. What has happened ?