What is MMX Technology & Why Was it Flawed? [Byte Size] | Nostalgia Nerd

PCs in the late 90s would most likely have been blessed with the terms MMX Processors. Pentium MMX, Pentium II MMX. For in 1997, Intel's MMX technology was all the rage, and the latest processor technology. If you didn't have an Intel processor with MMX extensions (or a Cyrix or AMD who quickly jumped on the wagon, much to Intel's displeasure) then you were about to fall behind the crowd, especially in terms of this new multimedia thing. CD-ROM based software needed some extra grunt and the source of this, according to Intel, would come from 57 new extensions encoded into their latest range of chips. However, in some cases it came at a cost to performance. Find out what that cost was and how MMX developed into something more useful with the Pentium II range of CPUs.

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Game at 4:10 is Pod. A racing game for the PC from 1997.

Digital data clip courtesy of BBC History of Computers series, aired in the early 1990s.

Information courtesy of "The Complete PC Upgrade & Maintenance Guide, Ninth Edition" by Mark Minasi.

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[herrfriberger]

The 64-bit MMX registers were overlaid on the 64-bit mantissa of the corresponding 80-bit FPU registers. This scheme was primarily chosen in order to make MMX compatible with MMX-unaware operating system kernels as it avoided the need to save any new registers on the machine stack during task switches. It had little to do with "enough room" (chip area).

It was possible to mix MMX and FPU code, although cumbersome, due to the fact that FPU registers are relatively addressed (a stack structure) while MMX registers are directly addressed. The Pentium II had the same limitations as the Pentium MMX in this regard.

(SSE then introduced a new separate register bank, making it much easier to mix SSE with FPU code, or even MMX code).

[morbid.]

CPU commercials from 90... Do we have cpu commercials now? I don't recall any.

[mrflamewars]

I am old and crusty and I remember people joking that MMX stood for "Much More eXpensive"

[ronch]

I love how every processor sold today still contains MMX.

[GoldenGrenadier]

good god Intel's marketing was awesome back then.

[denk]

I had to develop a buffer rotation library in IA-32 with SIMD instructions. I wrote several versions of each, from plain (we had to support very old processors) passing through MMX up to SSSE3.

The MMX version was the slowest of them all and required a lot more additional code to make it work properly (it absolutely needs the FP unit flushed before and after use). That was the same result I had when, later on, I had to build a 16 bits grayscale image normalization library.

[mikejones-vdfg]

I remember before MMX came out, reading about it getting all excited that the CPU is going to be better, games would run better without the need for better graphics cards.  That was the big thing I remember actually, the whole idea of getting better graphics without the need for a video card. The racing game you see at around 4:10 was  supposedly ran without a video card which was supposed show off the power of these new instructions.  At the time video cards were called 3d accelerators or something like that, but the point was that they weren't looked at as vital components to a computer, an extra booster type thing to have, which is why I think Pentium felt the need to include 3d acceleration to their processors with MMX.  Maybe they saw 3d cards as a thing that happened because they dropped the ball with graphics and this was their way of getting in the game.  But history showed that 3d accelators where here to stay and I think they didn't bother with being the "graphics" processor and let the gpu people do that.

[DazDaz]

Take of those early mmx CPUs were incredible in terms of overhead. My P166mmx ran happily at 287MHz. % wise that is the best over clock I have ever had by miles.

[Larry]

Can you do something on the failure of quadrangle graphics cards sometime dude?

[Icarus_Ridexx]

I remember that weezer video that came with Windows...

[MrDaveP]

I never imagined back in the 90s that MMX would become the subject of an enjoyable infotainment video 20-odd years later. It did have a use after all!

[verdatum]

I remember learning about this in my Computer Hardware course about a decade ago...and then immediately forgetting it. Can't forget the marketing though. God damn did they ever boast that feature.

[matsv]

Its not that the Pentium MMX cant run both MMX and FPU programs, it have to clean the pipleine. Its just a 7 or something steep pipline so its not really a issue if the software is well writen.

What really speed it up was AMD 3Dnow added floatingpoints to the SIMD instructions, basicly solving the problem and increasing the speed quite a lot.

[gnif]

MMX was not flawed, just misunderstood. Intel marketed it as a "media extension" whereas in reality, it is simply a more efficient method of performing integer math, and because it provided wide 64bit registers it is also very useful for high-performance memory copies where DMA could not be used. All modern memcpy implementations take advantage of SMID instructions where possible as it allows you to perform bulk memory copies far faster and in parallel. Even today MMX is still valid and is used depending on the task at hand. In fact, it was so successful and useful that it was later enhanced through the addition of SSE, SSE2, AVX and now AVX2 extensions that all operate using the same ideas and concepts.

[jessefoulk]

We bought a brand new HP Pavilion desktop computer that had this processor. 166Mhz w/ MMX. It was hot stuff back then. Near $2000 for it at Staples in early 1995.

[mikv]

MMX was actually designed to sell better. Intel was all about marketing and monopoly in late 90s.
I tested several CPUs from that era and it turns out, that Pentium Pro was actually a superior design compared to Pentium II clock per clock running an 200MHz both.
Also there's been a challenge for me to find ANY application that actually did benefit from MMX in Pentum II (Pentium Pro lacks MMX)
After benchmarking in many different apps and games from that era I found out that then considered obsolete Pentium Pro wasn't really obsolete and it did managed to finish almost every task faster than the same clocked Pentium II
The only app I found benefiting from MMX was Lame MP3 encoder which allowed Pentium II to be about 25% faster. Pretty nice boost actually but that was the only app I was able to found.

[Dazlidorne]

I remember getting a computer for Christmas and it didn't have MMX and the first week of January, they rolled out the new ones with MMX! I took my computer back and exchanged it. I didn't really know what it did, but I knew I had to have it.

[richiebob]

Dude i love this! your vids bring back many memories. Please make more :)

[TimLesher]

The cards at 2:49 aren't Intel video boards--they're various SoundBlaster models. :-)

The actual cards he's talking about are the Intel ActionMedia and ActionMedia 2 cards from ~1992 and ISVRPro from ~1994, both of which were i750-based if I recall correctly. The ISVR3 from ~1995 was the dumbed-down video capture board that offloaded compression onto the CPU.

I worked on the video software that shipped with the ISVR series. We never bothered adding MMX support to the software. Oops. ;-)

[SoranoGuardias]

That racing game is called POD. It's on GOG.

I loved the demo that came with my family's first PC in 1996. An Acer Aspire with a AMD K6 chip.