If this is a comparison of mobile GPUs and IGPs it very much depends on which Intel mobile CPU you are comparing. The IGP on the mobile Sandy Bridge processors all run at different clock speeds so you need to know what you're comparing.
Also you haven't specified which model of the GeForce 8600M you are using in the comparison. There is the GeForce 8600M GS and the GeForce 8600M GT. The GeForce 8600M GS has lousy performance.
On the Intel i5-2467M and i5-2557M the Intel HD Graphics 3000 performs worse than the GeForce 8600M GS.
The Intel i7-2760QM has the best graphics performance. Way better than the GeForce 8600M GT.
The ranking in terms of mobile graphics performance from best to worst:
GeForce 8600M GT
GeForce 8600M GS