VIA Apollo Pro 266: The P3 gets DDR

Haven't we been through this before?

The whole premise of our VIA KT133A review was to illustrate that the Athlon, in its current form, was not a memory bandwidth hungry processor leading us to believe that DDR SDRAM on the Athlon would not have the same effect as RDRAM did on the Pentium 4. If the Athlon isn't a memory-bandwidth hungry CPU, then the Pentium III is definitely much less of one.

Remember that the Pentium III was released with the assumption that people would be using PC100 SDRAM, and we saw the non-existent performance gain that pairing it up with RDRAM produced. In order to prove this theory, let's head back to our good friend Linpack and take a look at what happens when we compare performance between a Pentium III on a platform with 1.06GB/s of peak available memory bandwidth and one with twice that, 2.1GB/s.

As the data set gets larger than the Pentium III's L2 cache we can begin to measure the performance of its memory bus. Just like the Athlon, the Pentium III's performance does not skyrocket when paired with a memory solution that offers twice as much bandwidth.

A good comparison point here is the Pentium 4, which is based on an architecture that is so very memory bandwidth dependent that giving it 25% less memory bandwidth results in a 17% decrease in floating point performance, according to Linpack.

Unlike the Athlon however, the Pentium III is nearing the end of its lifespan. The only remaining update (Tualatin) to the current Pentium III core will revolve around giving it a lower power consumption figure and a potential for higher clock speeds courtesy, primarily, of a new fabrication process and a resulting die shrink.

The Athlon's outlook is much more positive. AMD has two more core updates on their current Athlon roadmap, the Palomino and the Thoroughbred. Although the Palomino may not gain the core improvements that we'd like to see outside of reducing power consumption, it would be a sin for AMD not to implement a few new features into the Thoroughbred core.

The bottom line is this: just as the Athlon did not respond to DDR SDRAM with astounding performance improvements, the Pentium III will most likely offer much less of a response.

Then why produce it? The potential for DDR SDRAM to be offered at a price point identical to that of PC133 SDRAM is much greater than the ability for RDRAM to do the same. In fact, we are fairly confident that DDR SDRAM will be presented in the very near future as a solution offered at prices that consumers were previously paying for PC133 SDRAM. With that in mind, combined with the marketability DDR in general, VIA would be insane not to produce as many DDR capable chipsets for as many different platforms as possible.