Note: this chapter presents some performance figures for LAPACK routines. The figures are provided for illustration only, and should not be regarded as a definitive up-to-date statement of performance. They have been selected from performance figures obtained in 1994 during the development of version 2.0 of LAPACK. All reported timings were obtained using the optimized version of the BLAS available on each machine. For the IBM computers, the ESSL BLAS were used. Performance is affected by many factors that may change from time to time, such as details of hardware (cycle time, cache size), compiler, and BLAS. To obtain up-to-date performance figures, use the timing programs provided with LAPACK.