Confused on how ram works for DDR2 on dual/quadcore

[V3LCR0]

I understand that in order to achieve a 400 FSB the ram needed to undergo this would be DDR2-800, but that seems a little bit too simple. The part i dont get is ram ratios with DDR2. I dont understand why 4:5 = 333 MHz : 883 MHz. Could someone please elaborate a bit more on what exactly that means?

 

[sutahz]

Well Double Data Rate (DDR) is as simple and multiplying by 2 (400x2=800). Surprisingly even math that simple can be a bit daunting for some, consider yourself lucky its 'a little too simple'.
Ratio, in your example, for every 4 steps on the FSB the RAM gets 5. 25% greater (5/4=1.25). 333/883? Ya lost me. From greysky's thread:
FSB : DRAM
1:1 = 333 MHz : 667 MHz
4:5 = 333 MHz : 883 MHz
2:3 = 333 MHz : 1,000 MHz
3:5 = 333 MHz : 1,111 MHz
1:2 = 333 MHz : 1,333 MHz

Oh now i see the 333:883, thats because you're taking 333, doubling it then adding 25%.
(333x2)x1.25=833.3.
So from this one example, i hope you can solve the rest of the problems

The 'exact' number using MS calc and having a FSB at exactly 333.3333333333333333333333333333MHz would be 833.33333333333333333333333333325MHz, but 833.3 rounds down to 833, much like 666.66666MHz rounds up to 667MHz. Real world, FSB is going to be around 332-335MHz and varies a little bit under operation.
Lower latencies is a hot topic, but my view is for 99.89% of the things out there its a moot point at best. Oh you said 'better for the ram' not better for performance. If anything higher latencies (timings) are better, puts it under less stress, allows you to run a lower voltage (probably).

Oh mis-saw what you typed. Looks like we found a typo for GreySky. Didnt see 883 was supposed to be 833.

 

[V3LCR0]

So the number would actually be 833.3 MHz, not 883 for a 333MHz FSB right?

 

[V3LCR0]

Also, would that mean running at lower latencys is better on the ram and overall performance of dual/quadcore, mainly in general for intel cpu's. Such as CAS timing, ect.

 

[flexy]

In general,

higher memory speed is better, also with higher latency. Speed always compensates for higher latency.
Goal of course to run your mem as fast as possible with lowest possible latency for that speed. I can NOT confirm that running CPU/RAM 1:1 is "better"...so, right now i am running Q66000 8x 442 and DIV 333/800 (==5:6 with mem at 530). Means CPU is overclocked, FSB is overclocked, and mem is overclocked.

Did many, many benchies and comparisons. Its the best right noe in terms of overall performance and latency.