Tecnically can DDR-II compete with Rambus ?

[idgaf13]

Intel seems to have taken a "detour" to use DDR RAM on its motherboards
But Rambus continues to hang in there.
At what point does support stop for either DDR or Rambus ?

 

[BumJCRules]

Until either of the technologies cannot keep pace with the bandwidth and system clock speed requirements, they will be in existance. Even after they are surpassed by newer technology, they will remain until there is no economical reason to exist. (I.E. EDO, Fast Page, etc.)

RDRAM is not a bad technology. Nor is DDR a better or worse than RDRAM. For all we know, AMD could use RDRAM as a memory type. All you need is a way to have the CPU talk to the modules. That is handled by the Memory controller, the Memory Clock Generator, and the DIMMs/RIMMs. So either type could uses DDR or RDRAM.

 

[Buddha Bart]

RAMBUS doesnt scale well in terms of size, as each module you add increases the latency. So its always going to be important for RAMBUS to have very dense modules, and multiple "short" busses.

SDRAM doesnt scale well either because its relativly high pin-count makes dual-channel configurations cost prohibitive, and its wide bus makes timing at higher clock rates difficult.

My guess is RDRAM will fade, not for any technical reason, but just because of its proprietary and must-be-licensed nature.

bart

 

[Locutus4657]

So that's why nVidia nForce boards are so expensive... For instance the Abit nForce 420 (with dual channel DDR) I found on price watch for $77.....

Originally posted by: Buddha Bart
RAMBUS doesnt scale well in terms of size, as each module you add increases the latency. So its always going to be important for RAMBUS to have very dense modules, and multiple "short" busses.

SDRAM doesnt scale well either because its relativly high pin-count makes dual-channel configurations cost prohibitive, and its wide bus makes timing at higher clock rates difficult.

My guess is RDRAM will fade, not for any technical reason, but just because of its proprietary and must-be-licensed nature.

bart

 

[ynotravid]

Originally posted by: idgaf13
Intel seems to have taken a "detour" to use DDR RAM on its motherboards
But Rambus continues to hang in there.
At what point does support stop for either DDR or Rambus ?

As soon as DDR blows past Rambus in BOTH speed and cost.

 

[Buddha Bart]

So that's why nVidia nForce boards are so expensive... For instance the Abit nForce 420 (with dual channel DDR) I found on price watch for $77.....

nForce's have a dual channel configuration, but they are not accessed in parallel, they are two seperate memory busses, so there is no need to ensure that thier timing works out perfectly.

a true dual channel (think of it as RAID0) DDR memory setup isn't even available in "consumer" level boards yet.
http://www.supermicro.com/PRODUCT/MotherBoards/E7500/P4DME-M.htm
http://www.tyan.com/products/html/thunderi7500.html
http://www.msicomputer.com/product/detail_spec/product_detail.asp?model=E7500_Master-LS

bart

 

[BumJCRules]

It will probably be which can scale better as CPUs increase in speed and FSBs vanish.

I think the Hammer is a good example of this. Since Hammer is intigrating the memory controller into the CPU, the CPU will rely on the memory bus directly.

This could be a good thing for RDRAM. It could make Yellowstone a viable option if it does not need a FSB and thus need to be translateded or harmonized with a non-equal bus speed. I agree with your statements with RDRAM and the latency issues. However latency becomes less and less important as frequency speeds increase.

 

[Labdog]

i don't think we are at the end of RDRAM & DDR.
to improve memory performances you need to increase the memory bus or the memory frequency.

32bits 533Mhz RDRAM single channel is coming out. 4.2GB/s bandwith. dual channel will involve 8.4GB/s.
by now Samsung works on 600 & 660Mhz memory.

DDR II specs from JEDEC are 400Mhz 3.2GB/s & 533Mhz 4.3GB/s then 666Mhz 5.3GB/s (1.8volt).
dual channel will double the bandwith as well.



note:
"JEDEC officials said the memory panel will now turn its attention to a DDR-III specification for a chip to follow in the 2004 to 2005 time period. Sources said DDR-III could be combined with the work of the Advanced DRAM Technology industry group, which includes Intel Corp. and a number of leading memory makers."

"In March 2001--prior to the development of the 512-Mbit DDR-II SDRAM--Samsung created a 2.5-volt, 128-Mbit DDR-II prototype for the joint evaluation project with IBM. In parallel with that effort, IBM created a first-generation DDR-II memory interface chip with a new registered dual-inline memory module (DIMM) for the new double-data rate II spec. "

"Samsung said the DDR segment is expected to represent 40% of DRAM sales in 2002 and will reach 66% by 2003. The DRAM market is expected to reach $21.1 billion in 2002 and grow to $41.1 million by 2004, said Samsung, citing a forecast from Dataquest Inc. "

"Samsung graphics DRAM goes at 1GHz
Semiconductor Business News
(07/11/02 08:05 a.m. EST)

SCHWALBACH, Germany - Samsung Electronics Co, Ltd. has introduced a 128-Mbit synchronous DRAM intended for graphics and networking applications based on the double data rate (DDR II) interface. The chip is capable of a data transmission frequency of 1-GHz and a data transmission rate of 32-Gbits per second, according to the company.

To achieve these data rates Samsung's 128-Mbit graphics SDRAM incorporates on-die-termination. The I/O voltage is 1.8-V and the chip is enclosed in a so-called fine-pitch ball grid array (FBGA) package.

Mass production of the 128-Mbit 1GHz DRAM is due to start some time before the end of September 2002.

Samsung claims to have 40% of the graphics DRAM market and the company reckons that the introduction of the 128-Mbit device should increase its share of the graphics DRAM market to 55% by the end of 2002."
from Silicon Strategies

 

[BumJCRules]

"Samsung claims to have 40% of the graphics DRAM market and the company reckons that the introduction of the 128-Mbit device should increase its share of the graphics DRAM market to 55% by the end of 2002. - from Silicon Strategies"

That is for graphics memory... That is very different than main memory. Yellowstone from Rambus is not a main memory either. It is wider and faster but that makes no difference to the main memory world.

 

[cheeta05r]

I want static ram. I know too expensive, but it would still rock.

 

[ynotravid]

?

 

[BumJCRules]

cheeta05r,

Nice to see you on another board. I still am looking for a home. Tom's has been boring lately and I get sick at looking at a dark screen at GenMay and Hard Forums.

Anyway... I agree. Static memory would gratly improve memory systems. I would like to see them impliment large casches of SRAM on the dies. Eliminate all that needlessly wasted space on the motherboard for channels, DIMMs, etc. Would be expensive but who cares. Speeds could scale evenly with the cpu. No ASIC needed to reconfigure the frequency differencesbetween the memory clock and the system/FSB clock.

As you said..."it would still rock."

 

[cheeta05r]

Ya, I sort of got board on Hard Forums a little, not enough traffic. I am also on amdmb forums, but it is a little fanboyish to me. There is way too much speculation about the amd processors. Just does not seem as inteligent. AnandTech forums seem more inteligent and least in this forum Highly Technical, but there is not as much traffic and the page loads are a little slow.

well anyway, after you get the cpu bus and memory bus synchronized you still have one major bottelneck, the harddrive. Even solid state drives are not fast enough. http://www.bitmicro.com/

 

[Smilin]

Just how expensive IS SRAM to produce?

It's what? about 6 times the die size for the same amount of bits. How well does it scale down (micron wise)?

 

[Agent004]

well anyway, after you get the cpu bus and memory bus synchronized you still have one major bottelneck, the harddrive. Even solid state drives are not fast enough. http://www.bitmicro.com/

I would love the 80 GBytes /s solid state hard drive from Cray (sp?)