Well people have got there by overclocking. I'm not sure how long but pretty soon 4 and even 5 will be standard, intel has said that they want to concentrate on other aspects of processors instead of Ghz, so they will probably be slow on getting there. There is new technology in the works which will drastically change the speed of the processor and they are also working on multi-core processors. MIT is also creating computer components from DNA so maybe in a few years our processors will be made from DNA, actual living pc's. Can someone say judgement day.
We will have to be patient rushing into creating super fast pc's could lead to them becoming self aware, we will have to have preventitive measures in place to stop them from creating their own reality. Who knows we could be part of one right now. Einstein and some others managed to get one to become aware and it became too intelligent too fast, they had to shut it down/"kill" it.