“MMX” originally stood for “MultiMedia eXtensions,” but now Intel, the developer of MMX, claims it doesn’t stand for anything – it’s just a brand name for an extension to the Intel Pentium chip architecture. First announced by Intel in March of 1996, the first generation of MMX-enhanced computers entered the market in January of 1997. MMX is found in enhanced Pentium and Pentium II chips, but not ordinary Pentium or Pentium Pros. I’ll try to eliminate the confusion about multiple Pentiums (Pentia?) in a future column.
MMX is actually a set of 57 additional instructions built into Intel microprocessor chips. This allows faster audio, video, graphics, and modem operations, but only from software written specifically to take advantage of MMX technology. Types of software that benefit from MMX technology are 2D/3D graphics, audio, speech recognition, video compressor/decompressors (codecs), and data compression. To get somewhat technical, MMX instructions allow operations to be performed simultaneously on more than one set of data at a time. These capabilities work on integer data only – that is, data that doesn’t contain any decimals or fractions.
In the past, additional chips have sometimes been added to a computer in a video or sound card to handle multimedia tasks without overloading the main processor. Called Digital Signal Processors, or DSPs, these coprocessors are now being replaced with MMX, which includes a “multiply-add” instruction that allows most of the capabilities of a DSP chip to be provided by the Pentium processor at very high speed.
Another feature of MMX is called SIMD: Single Instruction, Multiple Data. This means that a single instruction operates on multiple pieces of data in parallel. It allows the chip to reduce multiple compute-intensive loops common with video, audio, graphics, animation, and communications. According to Intel, “It’s like a drill sergeant telling an entire platoon, ‘About face,’ rather than commanding each individual soldier one at a time.”
A third improvement of MMX-powered Pentiums over their predecessors is more cache. On-chip cache size has been doubled to 32K, reducing the number of times the processor has to access slower, off-chip memory areas for information.
Do you need MMX? The most common employment of video, audio, graphics, and animation is in games; thus, people who play high-end games are the ones who will want MMX right now. Of course, Windows-based video editors, digital sound technicians, and computer animators consider it a must-have. Also, as multimedia becomes more prevalent on the Internet, MMX could become desirable in the short term for ardent web surfers. However, since mainstream productivity software like word processors, spreadsheets, databases, and checkbook or financial applications do not rely heavily on these multimedia components in their normal operation, MMX is not a requirement for ordinary business users at this time. However, Bill Gates and other industry leaders are predicting that some day we will not be controlling computers with keyboards or mice, but with our voices. Speech recognition could very easily be incorporated into everyday productivity applications – imagine dictating a letter to your word processor, or calling out numbers to your spreadsheet – so when that day comes, MMX could become a requirement.
Competitors of Intel such as AMD and Cyrix have managed to produce MMX-compliant chips, so an ad for a computer with MMX technology doesn’t guarantee genuine “Intel inside.” Not that that’s a bad thing, since some of these chips have out-paced Pentiums in head-to-head competition, and they generally cost much less, making the computers that contain them more affordable. In order to stay ahead in the chip wars, Intel’s next generation of chips, expected in early 1999 and code named Katmai, will have 70 more MMX instructions, called Katmai New Instructions, which will provide floating point, or non-integer, operations on parallel sets of data. So soon ordinary MMX itself will be obsolete, as more powerful chips continue to elevate our computing experience to new heights.
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