Does the Pentium MMX Live up to the Expectations?

Conclusion

The new Pentium MMX certainly yields at least some increased performance out of your system. In current Windows business applications it already runs about 16% faster than the Pentium Classic. As soon as MMX instructions will be used in all applications, the improvement may be considerably higher, particularly in image processing applications.

For the majority of the Windows business application users the Pentium MMX is certainly to be recommended. Don't forget that a Pentium MMX 166 is already faster than a Pentium Classic 200 under these circumstances and hence the Pentium Classic 200 should only be purchased if it is cheaper than the Pentium MMX 166.

However, for people who are using their computer mainly for gaming, which seems to be an increasing number, the Pentium MMX so far doesn't show much of an improvement. If you are belonging to this group, you can either stick to your old system, or you could get a MMX approved motherboard now and wait until the Pentium MMX gets cheaper. The prices of the Pentium Classic will drop soon, so if you want to get a CPU for gaming now, you might as well take advantage of the cheaper Pentium Classic. After all this CPU still is a good performer, which kept us happy until Jan 8, 1998.

To Microsoft I would like to address the message, that they should do something about their DirectX MMX support soon. Intel won't be too happy about the sad performance improvement under DirectX, but it would not be the first time, that Intel gets crossed by Microsoft. We only have to remember the problems a PPro has with the so called 32 bit OS Windows95. This was the reason for the tiny success of the Pentium Pro so far.

The 3D enhancement problem of the MMX instruction set seems to be more serious than expected. Here is an excerpt of an article from Microprocessor report, that is already 10 months old:

One drawback to MMX is the lack of a multiply or multiply-add for 32 bit operands. A fast 32 bit multiplier consumes four times more die area than a 16 bit multiplier, and Intel felt this feature was not worth the extra area. Besides, multiplication of 32 bit data can be performed using the standard integer multiply instruction. Although this instruction takes 10 cycles in the Pentium core and is not pipelined, it requires 4 cycles on Pentium Pro (and presumably Klamath) and, more important, is fully pipelined.

The integer multiplier, however, operates on the integer registers, not the MMX registers, and it cannot perform parallel calculations like the MMX units. Furthermore, there is no integer multiply-add instruction in x86. Because 16 bit precision is inadequate for advanced audio algorithms, such as wavetable sound, and for most 3D geometry calculations, the lack of a 32 bit multiply-add prevents these types of routines from taking advantage of MMX.

Cyrix and AMD will like the fact that so far only very few applications are taking advantage of MMX. The Pentium MMX release will push the software developers to create new MMX based applications, which probably will just begin to hit the market when their MMX CPUs M2 and K6 are coming out. That could be the perfect timing for them. Although Intel will soon release their new Klamath CPU, the competition for Intel will get harder. The M2 as well as the K6 are sounding pretty good so far. However, we will have to see if these CPUs will be able to live up to Cyrix's and AMD's promises. The past has shown that the great features of the Cyrix 6x86 couldn't really hide the huge problems with this CPU. The 6x86 is only now starting to become mature, but a P200+ is now considerably slower than a Pentium MMX 200. Let's hope that Cyrix and AMD have learned their 'Pentium Lessons' and that we will soon have a worthy competitor to the Pentium MMX and the Klamath.

One last thing I would really like to stress for the last time, so please read it carefully!!!!

The MMX capabilities of the CPU are completely untouched by the chipset! I still come across mails, where people claim you would need a particular chipset to fully use MMX. THIS IS NOT TRUE !!!! If some pseudo knowledgeable magazines try to make you believe this misinformation, then punish them by not buying them anymore! MMX is an extension to the CPU instruction set. It only can be used by software that's using these new instructions! Of course Intel doesn't try very hard to clarify this mystery, because Intel certainly likes you to buy new motherboards with the new upcoming 430TX Chipset. A MMX CPU doesn't mystically get faster due to this new chipset. This chipset is NO 'MMX CHIPSET', since it doesn't touch MMX at all! OK?