Hi all,
I think it’s one of the TinyMCE plugins (Ultimate and/or Advanced). I installed both yesterday and since today I’m having the same performance issues as you guys. I deactivated both plugins and even deinstalled them … still slow.
So I decided to install a new wordpress instance and imported all my other plugins, themes and settings. Now everything works fine again!
I am not sure whether it is the TinyMCE this plugin, but it really looks like it…
Cheers,
DeMaddin