Now at 17 hours.
The Boss fights..... OMG, the boss fights are absolutely insane! Just beaten Rennala, Queen Of The First Moon. The second phase was beautiful and I enjoyed a hell out of fighting her.
As for the performance issues, It seems it only happened when fighting tree sentinel. I haven't encountered another boss in the overworld quite like TS, but it was the only mini-boss in the game that was giving me the stutter hiccup.
Bro you did crazy main progress because im loke 12 or so hours in and i have barely beaten margit.