In a recent article on CNN.com it explains that IBM has created a transistor that has reached the speed of 500 Ghz. Perhaps we jumped ship from IBM a bit too early....
http://www.cnn.com/2006/TECH/ptech/06/20/ibm.chip.reut/index.html
http://www.cnn.com/2006/TECH/ptech/06/20/ibm.chip.reut/index.html
That speed was hit only when IBM researchers, working with counterparts from the Georgia Institute of Technology, cooled the transistor to near absolute zero, but Meyerson said the device still ran at 300 gigahertz at room temperature.