The performance issues you get by the end of the game (~40 hours, at the
area) are pretty bad. I'd say there is a serious memory leak at play, as performance seems to degrade over time played (though from a complete restart, you get back to bad performance reasonably fast in this area, so there is also something to do with the state the game is in at that point). You're looking at a lot of hitching, FPS drops (which are probably just micro-stutters), and the occasional 1-2 second full-stop hitch. Sometimes I thought the game was just going to crash on me, and it did, but only once. I really hope Bend / Sony can sort out those issues; I love this game, and have already finished it and am working on the platinum, so I'm accustomed to it, but it really blemishes a great product..
For reference, was playing on a PS4Pro.