“A limited number of IdeaPad U160 systems that were equipped with i5 and i7 CPUs and built before August 10th, 2010 were incorrectly manufactured. The resistor locations that select the CPU type installed were populated with values for the i3 CPU rather than the i5 or i7. As a result the Turbo mode does not function correctly, and overall performance is limited.”

— Re: U160 Turbo Boost broken?! - lenovo community