1.6GHz is just the idle frequency to save power.
i7-720QM will clock 2.4GHz with two cores on load, and 2.8GHz with one core on load.
http://en.wikipedia.org/wiki/Intel_Turbo_Boost
A new i7-720QM will be much faster than the old 2.6GHz Core 2 Duo, even at lower frequencies because the...