Limit on the speed of computers

How fast can a computer process its data ? In the past decades, the cpu simply goes faster and faster, as its size becomes smaller and smaller. However, there seem a limit, since it is not evident whether a sub-atomic circuit can be manufactured and manipulated. An electronic component can hardly be made tinier than an atom. Last year, two physicists argued that, in not more than 75 years, cpu cannot transcend itself anymore. Its speed shall saturate, a fact in spite of how the computer operates, be it classical or quantum.