to take or to not take

Test Preparation
1

well im currently a senior (international student - China) and i am likely going to take my IB exams next year due to medical reasons.

so i applied to top schools (ivies, stanford, CMU, berkeley)
and i intend to apply again. thus, i believe taking the SAT or ACT and scoring better would improve my chances.

i took the sat thrice and i didn’t take the ACT
SAT november 2013 - 1890 - (math 770, CR -520, WR - 660)
SAT may 2014 - 2070 - (math - 800, CR - 570, WR -700)
SAT november 2015 - 2190 - (math 800, CR - 650, WR - 740 (8 on the essay and 1 mistake - so the scaling was hard))

so is it worth taking the SAT or ACT worth it. i would have three solid months for it
i would like to apply to stanford rea - they dont have score choice.

so my questions are

  1. is it worth taking the sat a 4th time and is there a realistic chance of improvement?
  2. would colleges frown upon taking the sat again?
  3. if im retaking the test, would it be better to take the SAT or the ACT?

im science student btw and wouldn’t have a problem with the graphical analysis or science questions

all opinions are welcomed.
thank you for your time CC community

2

logically i would be looking for a 2300 + on the SAT or 34+ on the ACT if i retook