Proof please, thanks.
Just compare the gaming benchmarks
http://www.anandtech.com/show/3871/the-sandy-bridge-preview-three-wins-in-a-row/7
http://www.notebookcheck.net/NVIDIA-GeForce-320M.28701.0.html
E.g. MW2: 44FPS with Intel vs 69FPS with 320M
I know it's not sure what IGP it was in AT's tests and the drivers were beta and it had no Turbo etc but I would be surprised if Intel could actually come up with an IGP that can fight against 320M.