MMXTest detects your CPU type and performs MMX benchmarks. MMXTest is a simple program that detects what family of processor you have (8086, 286, 386, 486, pentium, pentium pro or pentium II ). It detects the presence or absence of MMX processing, tests the MMX instruction set, and performs a rough benchmark of your PC with MMX versus without MMX.MMX is widely believed to stand for "Multi-Media eXtensions", but actually stands for Matrix Multiplication. MMX computers have a special instruction which multiplies and adds at the same time. MMX machines also have improved caching, and run faster than normal Pentiums.