The good thing about the i7 processor is that it has a feature called turbo boost. That means that it can selectively overclock its processor cores when the overall processor load is low. This is a benefit for single-threaded applications like 3D modellers (like SU). I haven't got an i7 laptop myself, but I helped a friend choose one, and I seem to remember that the 1.73 GHz processor he finally chose can turbo-boost up to something like 3 GHz (you can find the exact specs in the Intel webpages). So it is likely that you shall be OK, but that there will not be a mind-shattering increase in SU performance.
Anssi