Crucial PC2100 DDR (Page 1 of 2)
Product sample provided by: Crucial
Date posted: 6/4/01
To the best of my knowledge DDR memory has been with us ever since NVIDIA started using it on their high end GeForce cards. Here recently we have seen many mainboard chipset makers go ahead and jump on the DDR bandwagon with AMD. At this point in time I believe the future of system memory is somewhat blurred. Although DDR has many benefits one of which is a low production cost. Some argue that the performance increase it has over SDRAM is not significant enough to justify a shift in the industry standard. Please be aware that I am addressing the area of system memory, as other memory applications may have a whole different set of needs and necessary considerations. My personal opinon is that we need to just wait and see how far DDR progresses. History has shown that time is needed for memory technologies to be refined and optimized. This usually happens through the development of mainboard chipsets better able to make use of the architecture. Consider just how far the KT133 chipset has come since its beginnings as the KX133.
Specifications and Features
The standard SDRAM clock speed has been 133MHz for some time now. Sure enough, DDR is most widely available in 133MHz as well. Of course, because DDR utilizes both the rise and fall of each clock cycle the effective throughput is significantly more. Some of you may be wondering about the name. The name PC2100 does not directly indicate the clock speed as with SDRAM. Rather the two followed by the one refers to the actual throughput, 2.1 gigabytes per second.
Another thing worth mentioning is the latency rating. While most SDRAM was rated at CL 3 or 2, DDR has raised the standard just a tad by using 2.5 and 2 as the choices.
Hopefully I have helped to clear up some questions you might have with regard to DDR in general and how it differs from SDR.
As some of you may have noticed, DDR sticks are on 184 pin dimms whereas SDRAM was packaged on 168 pin modules. For some visual comparsions I have used a generic 128MB stick of PC133 CAS2 SDRAM.
When looking at the back of the modules we can see that the SDRAM stick quite dusty. This is very significant as it means there is dust on the stick which is very signi... Argh, I hate getting hung up on brain loops. That usually happens when I don't have anything to say. So perhaps we should move on.