Advanced operating systems enable multiple programs to seemingly run in parallel by time-sharing CPU among them. This timesharing is known as multitasking. New applications using MMX instructions should be able to multitask with any other applications. An operating system does not need to know whether MMX technology is present, since it is hidden inside the floating-point state. Applications that check for presence of MMX technology, if it is built into the processor, they use the new instructions.
Many multimedia algorithms execute the same instructions on many pieces of data in a large data set.
Standard processors process only one piece of data with each instruction. MMX technology process several pieces of data with each data with each instruction - a simple type of parallelism that provides a big performance boost for many multimedia algorithms. As a result, MMX technology defines new data types, which are 64 bits in total size and are composed of independent smaller size data elements. Four data types are defined in MMX technology. MMX technology extends the basic instructions into SIMD versions.