Pentium MMX

Pentium MMX

Soon, more choices were on the way. About the time the 166-MHz Pentiums shipped, Intel introduced MMX (Multimedia Extension) technology, designed to enhance performance of data-hungry applications like graphics and games. With larger data and code caches, Pentiums with MMX technology can run non-MMX-enhanced software approximately 10 to 20 percent faster than a non-MMX CPU with the same clock speed.

To reap the full benefits of the new processor, MMX-enhanced software makes use of 57 special multimedia instructions. These new MMX operators use a technology called SIMD (single-instruction multiple-data) stream processing. SIMD allows different processing elements to perform the same operations on different data—a central controller broadcasts the instruction to all processing elements in the same way that a drill sergeant would tell a whole platoon to "about face," rather than instruct each soldier individually.

The MMX chips also take advantage of dynamic branch prediction using the branch target buffer (BTB) to predict the most likely set of instructions to be executed.
The MMX Pentium processor is also more compatible with older 16-bit software than is the Pentium Pro; consequently, it soon doomed the Pro to the backwaters of PC computing. All later versions of the Pentium have incorporated some variation of MMX and improved on it. The original Pentium desktop line ended with the release of the 233-MHz MMX in June 1997.