While computers have been increasing in speed continually month after month, memory has stayed relatively unchanged over the last three years - almost an eternity in the computer industry. Where the PC100 standard Intel set back way in 1998 was upped to 133 MHz (improving bandwidth of SDRAM theoretically by 33%), today's memory is being upped even higher to provide the hungriest processors with adequate memory bandwidth.

Yes there was the introduction of RDRAM, however it turned out to be Intel's worst nightmare rather then a widely embraced solution. Even though RDRAM has a large degree of memory bandwidth, it only has limited appeal because of the relatively high costs associated with latency. Compare RDRAM to that of DDRAM or SDRAM and you will also see a significant cost difference as well.

This is where DDR comes into play. NVidia were quick to recognize the benefits of DDRAM, and ultimately decided to shack up this double edged memory on their GeForce 256/DDR card. Originally the GeForce 256 only used SDRAM - which while being faster then anything else at the time was hampered by memory bandwidth problems. To help alleviate this, nVidia equipped the GeForce GPU with DDRAM and released it's true potential.

History shows us quite clearly that the difference between the original GeForce 256 card and the DDR adaptation is quite noticeable. Regardless of nVidia's efforts, chipset and memory manufactures liked the idea of DDR as it was relatively cheap to produce, had latency close to that of regular SDRAM, and by its very nature came pacing twice the memory bandwidth.

A new memory a new name

With the introduction of DDRAM came a few slight revisions to the naming conventions of memory. Now, the PCxxxx designation no longer refers to the speed of the memory but rather the full theoretical memory bandwidth of the module. For example, PC1600 DDRAM runs at a 100 MHz bus but has a total memory bandwidth of 1600 MB/s.

PC2100 DDRAM operates at a 133 MHz bus and has a total theoretical memory bandwidth of 2100 MB/s. Lastly we have PC2700 DDRAM. In this case, PC2700 means that this module was hand picked for its ability to run at a 166 MHz bus speed (very fast). PC2700 capable DDRAM is aimed directly at the performance market. So as long as your other components can handle the bus speed, your ram will no longer be the limiting factor when overclocking up to, and around 150 MHz FSB (front side bus).

On a side note: It should be obvious, but DDR has exactly twice the bandwidth of conventional SDRAM at the same bus speed. For example PC100 SDRAM = 800 MB/s, PC1600 DDRAM (at 100 MHz bus) = 1600 MB/s.

Anyway enough with the background, today I have the pleasure of testing a stick of TwinMOS 256 PC2100 DDRAM 7.5ns (PC2700 capable). I'll be comparing the relatively little known TwinMOS memory against the very popular Crucial PC2100 DDRAM we reviewed here previously and another 256 MB stick of Crucial PC2100.