Unstoppable: DDR400 vs. Rambus

[MadRat]

Try interleaved memory in this archived post. It should help explain a little bit better.

If you ask specifically about interleaved memory in Highly Technical then perhaps pm or Sohcan will help you out.

 

[Morph]

I stand corrected about the 32-bit PC1066 RDRAM that's coming out now. It only gives a bandwidth of 4.2 GB/s, as it says in this Rambus article.

However it looks like eventually there will be 32-bit RDRAM that actually doubles the bandwidth of a 16-bit module. First, look at the chart from the article here at TomsHardware: Text

It shows, in part:

PC1066 RDRAM Dual 533MHz 2x16bit 4.2 GB/s
PC1066 RDRAM Dual 533MHz 2x32bit 8.4 GB/s
PC1200 RDRAM Dual 533MHz 2x16bit 4.8 GB/s
PC1200 RDRAM Dual 533MHz 2x32bit 9.6 GB/s

Next, from an article about Rambus's memory roadmap: Text

"In addition to RDRAM device frequency increases, the RIMM module width will be increased from its present 16 bits to 32 and 64 bits. This extension effectively doubles and quadruples the RIMM module bandwidth. Combined with RDRAM frequency increases, Rambus has developed a PC memory roadmap that is easily scalable to 9.6 GB/s. "

I'm still trying to get a complete understanding of this stuff myself, but it sure seems like RDRAM has the capability to continue to outpace DDR, at least in terms of bandwidth, for the foreseeable future.

 

[BDSM]

Hi all Had to revive this thread.. Noone has posted for six days



Anyway.. I'm sure you read Anands review of the px333 chipset. Pretty impressive huh? I think so! A single channel of PC2700 DDR performing within -8 to +0.6 %.. With most scores around 95-96% compared to i850E with PC1066 Rdram!
And outperforming the 850E coupled with PC800 RDRAM in five out of seven tests!

Rememer that when these bords arrive they will be CHEAP! The cost of PX 266A boards is about 60 to 66% of an RDRAM based board today. The px333 will most likely be priced in a similar way.

It also offers USB 2.0!

Anyway.. I think it has been proven to us all that bandwidth isn't everything even for the P4!

I'm not saying the px333 will kill the 850E.. it won't, But maybe now you geeks will finally believe me when I say Dual channel PC2700 (and PC2100 too for that matter) will blow PC1066 Rdram out of the water performance wise.

And regarding the cost.. Well.. We'll see about that. DDR boards have a cost advantage today over RDRAM boards.. And even if this advantage disappears ppl will go for Dual channel DDR cuz of the performance. Ofcourse Intel knows this. And it is most likely the reason for them to dump RDRAM.

Regarding the long term roadmap from RAMbust.. Well.. DDR2 is probably not farther away than 32 bit pc1200 RDRAM , which ppl seem to talk about all the time. And dual channel DDR2 333 will yield 11.4 GB/sec.. which is if I am not entirely wrong more than the 9.6 GB/sec offered by dual channel 32 bit pc1200 rdram!

Anyway.. we really don't know shyt about how well rdram OR ddr/2 will scale.. so speculating farther than 6 months into the future is prolly kinda dumb.

 

[smp]

Bump~ I thought people were gonna post real world results here .. what happened?

 

[Zakule]

I figured that since nobody believed anything I was saying anyway, then why bother taking this any further. After my MS source told me that he had no intention of posting here, I knew it was a lost cause. Besides, RDRAM is back to being double the cost of DDR again. Until SiS or other chipset manufacturers put out some RDRAM chipsets then the prices will stay high. Even if you maintain that RDRAM is the better memory do you really want to pay twice as much for it? DDR, on the otherhand, is having the exact opposite problem. The prices are in danger of becoming too low for the companies to make acceptable profits (like what happened about a year / year and a half ago with SDRAM). Best at this point to wait for SiS's next RDRAM chipset if you're going to go that route, if only to save yourself some cash.

 

[Acanthus]

another argument to bring to the table is the fact that everyone on current non I850E boards doesnt support rambus of 115mhz, the DRCGs (direct rambus clock generators) on my TH7-II arent certified to run at any speed above 115mhz X4, and, of course, they dont run any faster than 120mhz X4, even with E/S PC1200 RD.