The purge will be the Garbage Collector kicking in, no idea what the surge is about. I see you have lots of plugins. When GH starts it loads all components from all plugins. Then information from these components is harvested (name, tab, icon, description) and then they are released again into the wild where eventually the GC will hunt them down and eat them.
If some of these components decide to do a lot of things inside their constructor methods, then that might explain the surge, however I don’t really want to point fingers at 3rd party developers without any concrete evidence.
The plugins themselves are loaded first of course, and all kinds of nasty stuff can happen there as well.
Can you load-protect all the plugins from the Preferences and see if it makes a difference?