Considering your monitor most likely only 60Hz, there is literally no difference between 200-150 fps. As your monitor can only display 60 fps at the most anyway. I really doubt you can tell the difference between those two framerates.
I think i stated this before. You cant really see a difference past a certin point.. but feel a difference. I think when it jumps up and down is when it causes the most problems. Is it unplayable?.. well if its bouncing up and down like an ADHD child on a bag of pure sugar.. probably. Hence, I think people who have large jumping like that in frame rate probably should get optifine and just check on the smooth FPS. that Will lower it yes, but it will stabilize it. It can be caused by having too many .. how do i say "ticks?" well at least "do something at tick". it can be like trying to read while having bad hiccups.I get like 10-70 fps and that's bad. Not because I think at that fps is unplayable, it's because the fps flunuates a lot. Why?