Rambus Demonstrates Superior Power Efficiency of World's Fastest Memory

[btarunr]

Rambus Inc., one of the world's premier technology licensing companies specializing in high-speed memory architectures, today showcased a silicon demonstration of a complete XDR memory system running at data rates up to 7.2Gbps with superior power efficiency. This silicon demonstration consists of Elpida's recently-announced 1Gb XDR DRAM device and an XIO memory controller transmitting realistic data patterns. The XIO memory controller is up to 3.5 times more power efficient than a GDDR5 controller, and the total memory system can provide up to two times more bandwidth than GDDR5 at equivalent power. In addition, the XIO memory controller demonstrated bi-modal operation with support for both XDR DRAM as well as next-generation XDR2 DRAM.

"Future graphics and multi-core processors require significantly higher memory performance under extremely challenging power and thermal constraints," said Martin Scott, senior vice president of Research and Technology Development at Rambus. "This technology demonstration highlights the outstanding power efficiency of the XDR and XDR2 memory architectures at performance levels from 3.2 to 7.2Gbps with scalability to well over 10Gbps."

This silicon demonstration, shown at Denali MemCon 2009 in San Jose, is the first implementation supporting the XDR memory architecture roadmap incorporating innovations developed as part of Rambus' Terabyte Bandwidth Initiative. Implemented in the bi-modal XIO memory controller for XDR2 operation, these innovations include:

• Fully Differential Memory Architecture (FDMA) - enhances signal integrity and increases performance through point-to-point differential signaling of clock, data, and command/address (C/A), an industry first;
• FlexLink C/A - reduces pin count and increases scalability; and
• Enhanced FlexPhase - enables the world's highest memory signaling rates while simplifying routing and board design.

In addition, the XDR2 memory architecture includes:

• Micro-threading of the DRAM core - introduced by Rambus in early 2005, increases data transfer efficiency and reduces power consumption; and
• 16X Data Rate - allows for extremely high data rates with the use of a relatively low-speed system clock.

Built on these innovations, an XDR2 memory system can provide memory bandwidths of over 500 GB/s to an SoC. A single 4Byte-wide, 9.6 Gbps XDR2 DRAM device can deliver up to 38.4 GB/s of peak bandwidth, and the XDR2 architecture supports a roadmap to device bandwidths of over 50 GB/s.

With these capabilities, the XDR and XDR2 memory architectures are scalable across a broad range of performance appropriate for multi-core computing, graphics, gaming, and consumer electronics. The XDR memory architecture has already been adopted in products including the Sony PLAYSTATION 3 computer entertainment system, DLP projectors, Teradici PC-over-IP computing systems, and Toshiba's Qosmio laptop PCs and HDTV chip sets.

View at TechPowerUp Main Site

 

[FordGT90Concept]

Rambus makes fast memory but because of their licensing tactics, it only gets used in proprietary hardware (ehm, it is extremely expensive by comparison to JEDEC standards).

 

[phanbuey]

very true... performance per watt isn't nearly as important for the consumer market as performance/$ - plus it seems like the i7, at least, is past the point of diminishing returns with mem bandwidth.

Then again... I don't think rambus is going for the consumer market - i doubt they will be releasing XDR sticks or that we will be seeing XDR motherboards anytime soon. This is probably just for manufactureres.

 

[FordGT90Concept]

Same for AMD. Integrated memory controllers really kill the necessity for extremely fast memory like we saw back in the RDRAM days.

 

[Deleted member 3]

very true... performance per watt isn't nearly as important for the consumer market as performance/$ - plus it seems like the i7, at least, is past the point of diminishing returns with mem bandwidth.

Then again... I don't think rambus is going for the consumer market - i doubt they will be releasing XDR sticks or that we will be seeing XDR motherboards anytime soon. This is probably just for manufactureres.

Same for AMD. Integrated memory controllers really kill the necessity for extremely fast memory like we saw back in the RDRAM days.

Read the part where they mention GDDR5 and graphics and rethink your arguments.

 

[phanbuey]

Read the part where they mention GDDR5 and graphics and rethink your arguments.

"With these capabilities, the XDR and XDR2 memory architectures are scalable across a broad range of performance appropriate for multi-core computing, graphics, gaming, and consumer electronics."

Read the whole article, so you know which part of it we are talking about. We're basically saying that graphics and consumer electronics are really the target markets, as XDR is cost prohibitive as a competitor for DDR3 and consumer multi-core computing.

 

[Deleted member 3]

"With these capabilities, the XDR and XDR2 memory architectures are scalable across a broad range of performance appropriate for multi-core computing, graphics, gaming, and consumer electronics."

Read the whole article, so you know which part of it we are talking about.

I read it, I read that. You state faster RAM is quite useless. I'm pointing out that this, like you said, for a broad range of applications. Graphics being one where it definitely can make a difference.

 

[FordGT90Concept]

XDR costs many times more than GDDR5 which hurts the card manufacturers bottomline. Rambus, as always, isn't that practical unless the consumer base is willing to pay the premium (e.g. PS3).

 

[phanbuey]

I read it, I read that. You state faster RAM is quite useless. I'm pointing out that this, like you said, for a broad range of applications. Graphics being one where it definitely can make a difference.

I was referring to x86, consumer-level cpu platforms only without making it clear - ie. the performance difference of i7 between dual and triple channels and between 1066 and 1600MHz DDR3. Graphics and other consumer tech are a completely different story.

 

[Deleted member 3]

You were clearly referring to that, which is why I pointed out that it's not just for such markets. Repeating your point would just make me tell you that again.

 

[phanbuey]

You were clearly referring to that, which is why I pointed out that it's not just for such markets. Repeating your point would just make me tell you that again.

I never said that it was just for such markets, nor did I preclude the technology from other applications. I just said that it didn't apply to that particular one, but thank you, once again, for pointing that out. Again.

 

[btarunr]

XDR costs many times more than GDDR5 which hurts the card manufacturers bottomline. Rambus, as always, isn't that practical unless the consumer base is willing to pay the premium (e.g. PS3).

How many times more? Can you draw an estimate?

I estimate that if it cost even 1.25 times more, nobody would have bought it.

 

[Ketxxx]

RAMBUS is impressive, always has been. Thats the bottom line. HOWEVER, the insane price puts it beyond commercial mainstream use - its not cost effective. You can see such memory being used in space shuttles, scientific satellites, and things like that because you want nothing but the best in those situations. For everything else though, its pointless because its not cost effective. A simple scenario;

SETI researcher: "Hmm.. how many more PCs can I hook up?"
Student: "What about a system using RAMBUS memory instead?"
SETI dude: "Nah. 1 system + RAMBUS = the cost of 4 PCs"

Price makes RAMBUS impractical.

 

[btarunr]

For most of us, this dogma of "rambus is expensive" circles around how RDRAM was expensive compared to DDR-SDRAM or SDRAM, back in its day, when it was the fastest memory standard, and could ask any price for the performance. The IP drama pushed RDRAM out of the PC memory industry, not necessarily that DDR-SDRAM was cheaper and emerged the 'winner'.

I don't think XDR is an expensive standard. If it was, Sony wouldn't have opted for it against competitive DRAM standards (for use in PS3) or the several other products that use XDR. In the market, price fractions as small as 0.1 (10%) can tilt the deals in favour of either standards, when sourcing of raw materials. Presuming such a small price difference exists, Rambus can play the performance/price card and emerge as a viable option or standard.

 

[Steevo]

Don't count Intel out yet, they have tried to move this in the past, failed with it. But that doesn't mean they will learn a lesson.

 

[[I.R.A]_FBi]

Don't count Intel out yet, they have tried to move this in the past, failed with it. But that doesn't mean they will learn a lesson.

Im worried by this statement

 

[Ketxxx]

A 10% difference in material costs is substantial. As a businessman lets give a basic example. Lets say 10,000 units of DDR3 costs £5000, and the cost of 10,000 units of RAMBUS is £5500 (+10%). For the sake of the example lets take the PS3 which uses RAMBUS, and compare it to a competitor that chose to use the cheaper but just as good DDR3. Leaving out many other factors to keep the example as simple as possible lets say the base unit cost of the competitors console is £275, to cover the costs of the more expensive RAMBUS in the PS3 the base unit cost of the PS3 must be +10% per unit sold. This makes the base unit price of the PS3 £302.50. On a consumer level, that £27.50 price difference is quite substantial.

 

[FordGT90Concept]

How many times more? Can you draw an estimate?

I estimate that if it cost even 1.25 times more, nobody would have bought it.

It has to be more than that. The only indicator of pricing I know of RDRAM versus PC-133 and DDR-266. It was 2-4 times more expensive for the same amount of memory (still is). Of course, it didn't help that you had to have two sticks all the time too.


I think what it really comes down to is this:
-DDR has strength in numbers with dual-, tri- and quad- channel memory controllers and the possibility to go even higher (especially with FB-DIMM). This makes sense because DDR2 is/was cheap.
-In new computers and servers, you always want at least 1 GiB and most computers ship with at least 2 GiB.
-XDR is found in devices, like the PS3, with 512 MiB or less memory--very low densities. I can't think of a single application where XDR used exceeds 1 GiB.
-XDR can achieve higher bandwidth without many chips/sticks.

XDR, therefore, is cost effective when you don't need much memory and the memory you do have has to be fast (e.g. HDTV devices, PS3, etc.). DDR3/GDDR4 makes sense when you need a lot of memory. Because video cards are moving into 2 GiB VRAM territory, video cards are already out of the market for XDR. Vista doesn't like any less than 2 GiB either so your average computer is also out of the market for XDR.

 

[Ketxxx]

I'd like to see a console use 1600MHz DDR3 vs some RAMBUS stuff. Equal densities of course. I bet it wouldn't make a jot of difference eitherway performance wise.

 

[Steevo]

I want a 2GB graphics card.