Safari lagging

Safari is unusable for me as well. MacBook Air (2012, 8G). If I open a private window everything works great. As soon as I open a normal Safari window the application takes up over 2G more application memory and becomes nearly unresponsive. I've cleared caches and removed all plugins and that didn't help. I don't see anyone mentioning a bug report so I'll do that.

Same here (beachball/hang when switching tabs), spindump hogging CPU in the Activity Monitor.

Safari has been hit and miss. When it crashes it does this all the time. Then it can be stable for a while, Reboot normal sorts for a bit. Though it is still in beta, so will wait untill it is sorted.

Having same issue. Seems to be related to JavaScript interpretation or interaction with the macOS keychain. Not sure yet.

My other posts on this (because search does not give great results sometimes)

Safari 10 Locks Up on Certain Sites

Safari 10 Stalling / Locks Up (PWOD)

and here they report a crash which may be linked to same issue?:

Safari 10 crash on macOS 10.12