[Tinibree]

I'm having the same problem, it's only on my 110 character that I have the framerate issue and it's only been a thing since after I unlocked WQs, I thought it was a different addon (broker world quests) at first since it was the only thing I'd added. It's been on and off since then (which is a week ago now) so it could very well be a wardens quest thing, which I didn't do and thus got moved off the map. I'll go do the warden's quest and edit this to say if it fixes it or not.

Edit: Upon death of the 4th wanted, framerate spiked up to 30. Heading to turn in the quest and see if that gets me back up to 90.
Edit 2: Nope, quest completion stayed at 30fps, but map open still brings me up to 90. Very confused but at least my framerate is better.

I didn't even noticed that the blizzard map brought the framerate back up until someone else pointed it out. Map open gives me 80-90fps map closed gives me 10, it was giving me even less but i disabled other addons trying to find the problem that got it up to 10. I can only guess with the map closed it's trying to reach info it can't get about world quests.