Amdahl left his eponymous company in August 1979 to set up Trilogy Systems, together with his son Carl Amdahl and Clifford Madden. With over US$200 million in funds, Trilogy was aimed at designing an integrated chip for even cheaper mainframes, but the chip development failed within months of the company's $60 million public offering; thereafter, the company focused on developing its VLSI technology and, when that project failed, in 1985, Trilogy merged into Elxsi. Elxsi also did poorly and Amdahl left in 1989, having already founded his next venture, Andor International, in 1987. Andor hoped to compete in the mid-sized mainframe market, using improved manufacturing techniques developed by one of the company's employees, Robert F. Brown, to make smaller, more efficient machines. Production problems and strong competition led the company into bankruptcy by 1995.
Amdahl was elected Distinguished Fellow of the British Computer Society (DFBCS) in 1979 and in 1983, Amdahl was awarded the Harry H. Goode Memorial Award by the IEEE Computer Society "in recognition of his outstanding contributions to the design, applications and manufacture of large-scale high-performance computers."