The ILLIAC 's design was finalized in 1966 with 256 processors .
The ILLIAC 's design was offer speed up to 1 GFLOPS , compared to the 1970s Cray - 1 's peak of 250 MFLOPS .
The ILLIAC 's design was finalized in 1966 with 256 processors and offer speed up to 1 GFLOPS , compared to the 1970s Cray - 1 's peak of 250 MFLOPS .