Being highly intelligent isn't related at all to having common sense or lots of knowledge - you need broad experience to gain those things. So who's made you ask this question?
Intelligence is not as easy to measure as it was once thought to be Also a poor grasp of social skills may be found in many people considered to be very intelligent. Autism/Asperger's Syndrome is often found in people who would score highly in an I.Q. test.
I agree , the line between the genius and the daftie can get blurred. My nephew is a prime example. His grades at school were amazing, and as a result he is at Uni becoming an ologist is something or the other. A few years ago when he was 14/ 15 he nearly burnt his father's house down testing a claim on a tin of hairspray or deoderant ( can not remember ) was actually as flammable as stated. He managed to burn a big hole in his bedroom carpet. !! Lesson learnt.
IQ seems to be to do with the processing power/speed of the brain. Nothing to do with amount of data in that brain, or whether the results of that processing make sense.
oh yes , years ago my neighbour's son was a physics graduate ,but when he gelped me upstairs with the xmas tree (we lived in a town house ) , the tree was too tall and so he cut 3 foot ......off the top!