Student or Learner
1). I am not good at science but beside Ken I am a genius.
2). I am not good at science but compared with Ken, I am a genius.
Are the above sentences correct and same in meaning?
Sentence 1 is unnatural. You might be OK if you say "... but next to Ken, I am a genius". It doesn't work with "beside", even though in some contexts "beside" means "next to".
Sentence 2 is correct.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.