Intelligence is not about problem solving but understanding. I can explain some complex topic to someone less intelligent ten times in all the ways I can imagine it being explained, I can try to break it up into pieces, I can try to take the pieces even more slowly... but in the end, if the person does not have the capacity, they don't grasp the whole picture.

Oftentimes intelligence translates into speed: speed of understanding new concepts; speed of doing things, but far from always. In fact the latter is typically just practice, no matter how smart you are.