Comparative performance evaluation of two supercomputers: CDC Cyber-205 and CRI Cray-1

This report compares the performance of Control Data Corporation's newest supercomputer, the Cyber-205, with the Cray Research, Inc. Cray-1, currently the Laboratory's largest mainframe. The rationale of our benchmarking effort is discussed. Results are presented of tests to determine the speed of basic arithmetic operations, of runs using our standard benchmark programs, and of runs using three codes that have been optimized for both machines: a linear system solver, a model hydrodynamics code, and parts of a plasma simulation code. It is concluded that the speed of the Cyber-205 for memory-to-memory operations on vectors stored in consecutive locations is considerably faster than that of the Cray-1. However, the overall performance of the machine is not quite equal to that of the Cray for tasks of interest to the Laboratory as represented by our benchmark set