Are u sure u don't read it wrong?
HD 4000 is at rank 47. lowest 7670m is rank 34,
7670m is way more powerfull if u compare it with HD 4000 (score 1060 vs 590) from the link..
My bad!!! i cmpared the intel hd 4000 desgined for desktop computers with the amd 7670m graphics card.....anyway thnx..:)