Definitely the AMD one is better than the Intel HD 4000... if my quick research is to be believed. :lol:
The HD 7670M is about the same level as a discrete HD 6670 (both has 480 SPUs, 24 Texture Units and 8 ROPs) though I'm sure the Mobility one has a lower clock rate. But nevertheless, I believe it still is a heck of a lot faster than the Intel HD 4000.