Difference between DDR Pc2100 & Rambus Memory?

[Hyp]

Other than the price what is the difference between DDR pc2100 & Rambus memory? Isn't Rambus the fastest out right now? Is there enough performance difference to spend the extra on Rambus? Thx.

 

[sohcrates]

rambus is definitely faster, and it's definitely more expensive. BUT, rambus is used in pentium 4 systems, while DDR is used in athlon systems. so the ram is NOT interchangeable.

what processor do you / are you planning on running? that will decide what RAM you can use

 

[Dark4ng3l]

Rambus is serial memory. The data path is 16 bits wide and the information has to pass through each chip in the entire memory configuration to reach it's destination(the more modules you have the more latency). RDram also has terrible latency. DDR SDram is paralel 64 bits wide datapath. Sends 2 bits f information each clock cycle(DDR), has worse latency than sdram but alot better than redram. Also you cant run rdram on an AMD platform and I dont think there are any chipsets that support DDR sdram for the p4 right now anyways so a direct comparision between the 2 is irrelevant.

 

[Hyp]

A P4 1.4 & 256 Mushkin Rambus Ram is what I wanted to go with.

 

[ragiepew]

<< rambus is definitely faster, and it's definitely more expensive. BUT, rambus is used in pentium 4 systems, while DDR is used in athlon systems. so the ram is NOT interchangeable.

what processor do you / are you planning on running? that will decide what RAM you can use >>



exactly what do you mean by rambus being &quot;faster&quot;? If raw MHz is concerned then you are right... if performance is what you mean then its questionable. Rambus in a single channel versus DDR single channel is a win for DDR (pc2100 anyway), due partly to a throughput advantagve of single channel DDR and the higher latency exhibited by RDRAM. In a Dual channel solution (as w/ the p4), RDRAM has a nice speed avantage (3.2GB/s i blieve) versus single channel DDR. Soon though, dual channel DDR based boards will be out (nForce) that &quot;should&quot; outperform dual channel RDRAM due to the raw bandwith advantage (4.2 v. 3.2). In any case, they are both fast and for a more technical evaluation between the two (something I am not really able to provide) go on over to the spanking new &quot;highly technical forum&quot; and read and/or ask a question.

Highly Technical Forums

Also try this link... for some RDRAM latency issues...

 

[thorin]

A quick Search of the forum will answer you question.

?RDram and DDR ram
?What is the difference between DDR Ram and RDRam?
?DDR vs. RDRAM at Computex:
etc...

Thorin

 

[sohcrates]

i was basically going off of my sisoft sandra results. my system got spanked by the p4's rambus memory subsystem results...they were off the charts. just seems like rambus has the edge right now.

edit: of course, my athlon 1.2 kicked a p4 1.4's butt in the cpu benchmarks!

 

[ragiepew]

you are right that in a synthetic test such as sandra, the memory benchmar (which is one of the better sandra benchmarks) yields a strong advantage to the p4's memory architecture (dual channel). I believe, and this is not fact because no benches have been provided to support this, yet, that the dual channel DDR solutions will also do quite well in sandra memory benches... Remember though, that sandra does not reflect real world applications... though it has been proven in some apps, multimedia stuff and q3a for example, that the extra bandwith is quite useful.

alin

 

[Maverick]

right now Rambus has more bandwidth since its dual channel. Soon with chipsets like the Nforce you'll see dual channel DDR. Then DDR will be theoretically faster. The latency time on Rambus is longer but the dual channel makes up for it right now.

As for whether Rambus is worth it, that all depends. If you're willing to spend twice as much so you can have lots of bandwidth now instead of waiting 1-3 months and getting bandwidth for half the price...I guess rambus would be &quot;worth&quot; it.

Also keep in mind you're limited to only P4 processors with Rambus. Once the P4 is out you won't be able to use your RDRAM with any other chip since Intel will move to DDR or QDR.

 

[Insane3D]

With new technologies like the Hardware Prefetch of the Athlon 4, DDR is starting to get close to RDRAM levels (PC600) with some overclocking. For instance, in Sandra I get a 904/1011 score on my Athlon 4 system with 256mb of Crucial DDR (PC2100) @ 161FSB. This is very close to the levels of PC600 RDRAM but without the latency. When DDR yields get even better and they overclock better, like the upcoming PC2700, the performance advantages of RDRAM may be even less...only time will tell.