Moore's law has been stagnant lately. Many of us only buy a new computer when the technology makes at least one e-folding of progress since the time of our old hardware. We only remake lyrics of songs when a change from 20 megabytes to 20 gigabytes is needed to preserve the spirit of the song. The fastest microprocessors seem to have been around 3.6 GHz for quite some time.
However, the situation may change soon. IBM, a company with very skillful physicists on board, will present their POWER6 microprocessor that will run almost at 5 GHz. Moreover, the company proved that they can overclock that processor and take it up to 6 GHz which could become a standard frequency of the commercially sold microprocessors as soon as next year. See news.google.com.
What does Intel have to do to beat IBM's 6 GHz? How do you get from topological string theory to topological M-theory? Yes, your answer is correct: they must go to 7 GHz. ;-) I am not sure whether they are as brave as the Japanese enthusiast who did it with his Pentium 4.