The pipe being the main culprit makes more intuitive sense than most other possibilities, imho.
It just seems that database or other coding errors would cause sporadic / unpredictable poor performance, quite unlike the 'special event' logjams that occur here, almost like clockwork.
Possibly having the everything routed through a Tokyo backbone isn’t helping much, either.
I was just snooping around and there are literally tons of forum specific web hosts available.
No muss, no fuss and no errors.
Pros run the databases.
If it were my website, I’d be moving to one of them.