There is a lot of classified work on GaAs for communication links where the speed of demodulating/modulating a signal is critical. But for general computing, i

There is a lot of classified work on GaAs for communication links where the speed of demodulating/modulating a signal is critical. But for general computing, implementation is more critical, consider that the Cray T3E sustained 1 teraflop of computing power, while 3 years ago the Cray-3 could sustain only a meager 16 gigaflops - clearly silicon could deliver performance (and it does so today!).