MMX

After the Pentium was developed, Intel introduced a feature called MultiMedia eXtensions, or MMX. MMX added 57 new instructions that were built into the processor and told the system how to work with audio, video, and graphics. If these instructions were not built into the processor, the processor would have to retrieve them from somewhere else.

At the time MMX was developed, both the home and business user seemed to be heading toward the world of multimedia, and it made sense to enhance the processor and make it "multimedia-aware." Running any kind of multimedia application on a processor that supports MMX gives you a major performance increase over a processor that doesn't support MMX technology.

Hyperthreading

Hyperthreading is a feature designed by Intel that was placed in the Pentium processors. Hyperthreading technology, or HTT, allows a processor to logically act as two different processors by being able to execute simultaneous threads. A thread is a part of an application that executes at any given time. For example, when running Microsoft Word, one thread accepts keystrokes, and another thread runs the spell checker while you type - two parts of the application run at the same time.

In order for a system to truly be able to take advantage of multithreaded applications, you normally need a system that has multiple processors - one processor to run one thread at a time. With hyperthreading, one processor is able to run more than one thread at a time, increasing performance by 15 to 30 percent.