DDR memory question. HELP!!!

[Sunny129]

all the time i see DDR memory referred to in different notations, and i don't quite understand it all. i think i understand this much:

1) when it is referred to as DDR333, 333MHz is the clock speed at which SDRAM would have to operate to achieve the same data transfer rate, so the DDR333 is actually running at 166MHz...please correct me if i'm wrong here
2) when it is referred to as PC2100, 2100MB/s is the theoretical maximum bandwidth the memory can achieve.

how do these numbers relate to each other though? is there some formula i can follow to figure out the theoretical maximum bandwidth of my memory if i know its DDR333? and conversely, how can i figure out the clock speed if i know i'm using PC2100 memory?

thanks...eric

[Sunny129]

the good thing about this message board is that you can see the # of people who view your thread vs. the # of people who actually respond. DDR has been around for quite some time now...i thought for sure that someone could answer my questions

[blade]

Probably because most who viewed this don't know the best way to explain it. Perhaps this will help some.
http://www.overclockers.co.nz/ocnz/misc ... de/1.shtml

[FlyingPenguin]

Blade asked me to answer this one, but to tell the truth I'm still in the stone age here. All my systems and my clients use SDRam and I'm not familiar myself with the naming conventions used for DDR Ram.

A quick search on Google, however, turned up this page which seems to have a good explanation: http://www.karbosguide.com/hardware/module2e5.htm

So yes, it appears you are correct in your assumptions. Looks like the 4 digit spec (aka PC2600) is indeed a reference to the "theoretical max" bandwidth. Why they can't just use the clock speed is beyond me - that's the way we've done it until now.

There's a chart on that page which lays it out: