That's a bit misleading and an oversimplification. The simplest way to explain what is wrong with that statement is encapsulated in one word: Amithlon.
That's probably not true.
Remember the old Geforce-II Ultra benckmarks? A 700Mhz P3 gave nearly identical FPS in all test against a 1.6Ghz P4.
And *YES* I would rather have a faster CPU than 600Mhz. 1Ghz would have been a better starting point, bit I can live with 600Mhz as a start!