Just a few months ago, Jacket 1.4 was released sporting an improved MTIMES routine that brought about radical improvements to Jacket's matrix multiplication. The quest for performance never ends though. Now, in the release of Jacket 1.5, MTIMES is even faster than before for SGEMM routines.
Checkout the MTIMES Benchmarks wiki for more information. I you are attending GTC, you may want to attend this session also!
