What definition are you using to say chimps don't have human level intelligence?
By any useful definition, the intelligence of human ancestors very closely resembled that of chimps for about 4 million years after the human and chimp lineages diverged. While it's impossible to say for certain, that's around the time that endocranial volumes started growing consistently beyond the range seen in chimps. That is also around the time of the first evidence of stone tool making.
