Gigabit XDR module developed

[one]

Current 2 XDR chips in a PS3 can be combined into one with this new chip. It's a good sign for the first month of the next fiscal year though the actual day and date is up to their strategic decision.

http://www.elpida.com/en/news/2009/01-20.html

Elpida Introduces Industry's First x32-bit 1-Gigabit XDR™ DRAM
The World's Fastest 7.2GHz XDR Product

TOKYO, JAPAN, January 20, 2009 – Elpida Memory, Inc. (Elpida), Japan's leading global supplier of Dynamic Random Access Memory (DRAM), today introduced the industry's first 1-Gigabit XDR™ DRAM based on a x32-bit configuration. The new XDR product features the industry's fastest ultra-high speed of 7.2GHz, which is faster than any GDDR5 memory chip, and provides a data transfer rate of 28.8 Gigabytes per second with a single device, making it an ideal choice for such high-bandwidth, high-performance full HD-capable applications as game consoles, digital televisions and Blu-ray disc recorders.

"Today's consumer electronics require both high performance and superior power efficiency," said Sharon Holt, senior vice president, Licensing and Marketing at Rambus. "Elpida's leadership with the award-winning XDR memory architecture makes possible a range of great products for consumers to enjoy."

The XDR device is manufactured using Elpida's 65nm process technology and utilizes a 1.5V low voltage operation and an x32-bit interface. It provides a one-chip solution that, compared with two x16-bit configuration 512 Megabit XDR DRAMs, consumes 35-40% less power and requires less space.

"In today's era of digital convergence many existing digital consumer electronic appliances are connecting to the Internet and the use of high compression codecs like H.264/AVC is spreading. This means there is now even more demand for greater bandwidth and higher density memory," said Yoshitaka Kinoshita, Elpida Memory's executive officer in charge of the Mobile & Digital Consumer Division. "Our newly developed 1-Gigabit XDR provides incredibly high bandwidth with lower operating power to meet the systems needs of our customers. Elpida will continue to focus on reducing the power consumption of XDR DRAMs, which we believe can also lead to tremendous application potential in portable devices."

Sample shipments of the new XDR have already started and mass production is scheduled to begin in April 2009.

As a top supplier of XDR DRAM, Elpida continues to specialize in developing high-performance, low-power XDR products.

 

[Zassk]

If mass production begins in April, then it stands to reason that availability to a company like Sony comes later, and consoles containing them probably reach store shelves 6 months after that. Whatever innovations we see in the PS3 this year will be the result of products that went into mass production in late 2008.

 

[wco81]

What else is using XDR these days?

And is the PR correct, it's still the fastest RAM?

 

[Crossbar]

It´s a new type of XDRAM, twice as fast as the one in the PS3.

 

[Mintmaster]

And is the PR correct, it's still the fastest RAM?

It depends on how you count the bandwidth. XDR uses differential signalling, so the x32 data bus actually needs 64 traces. That means a pair of 32-bit 3.6 GHz GDDR5 devices connected with the same number of data pads on the chip will give you the same bandwidth. That's been around for some time now, and I'm sure the best chips are even faster now.

I don't know the nitty gritty details, but I don't see the advantage of XDR.

 

[marcus_rocks]

Current 2 XDR chips in a PS3 can be combined into one with this new chip. It's a good sign for the first month of the next fiscal year though the actual day and date is up to their strategic decision.

http://www.elpida.com/en/news/2009/01-20.html

You cannot have double capacity chips to replace the old ones because of the number of buslines that run straight to the IO-controller of the Cell processor unless the new chips has twice the number of pins as the old chips or you change the cell's specs.

 

[Crossbar]

I don't know the nitty gritty details, but I don't see the advantage of XDR.

Here you can find some opinions on the matter.

This is Rambus view:

"Ultimately, the industry will have to switch to differential technology", said Michael Ching, director of product marketing at Rambus. A Qimonda white paper shows today's techniques running out of steam at 5 to 6 GHz, he said.

"That's pretty much the end of the line for the single-ended approach," Ching said, adding that the Rambus XDR approach can consume less power than single-ended techniques. "Our analysis shows differential technology results in lower power even at 4 GHz or so, and the difference between the two grows as you go faster," he said.

The Rambus XDR technology is available at data rates from 3.2 to 4.8 GHz and will scale to 6.4 GHz. Within weeks, Rambus will disclose its XDR-2 technology, which will start at 8 GHz and has been demonstrated at 16 GHz, Ching said.

The competition partly agrees:

Macri said advanced signaling technologies from Rambus will not be competitive, in part because they use a differential (two-wire) approach rather than the single-wire technique in GDDR5. The extra wire typically requires more pins and power. "We don't think a differential solution make sense until you get to speeds of 8 to10 Gbits/s," he said.

7.2GHz is almost there.

 

[Crossbar]

You cannot have double capacity chips to replace the old ones because of the number of buslines that run straight to the IO-controller of the Cell processor unless the new chips has twice the number of pins as the old chips or you change the cell's specs.

I wouldn´t be surprised if the chips provide a compatibility mode at half speed, it is usually easy to go in that direction.

If so and if the price eventually becomes competetive, it sure would make sense to use it in the PS3, less chips and less heat.

There is also the possibility that the new 45 nm shrink of the Cell has support for the new memory and could possibly use it down clocked in the PS3.

 

[Arwin]

So just for keeping things clear, the PS3 has four XDR RAM chips now right (2x 2x16bit 512kbit)? And these could be consolidated into two XDR RAM chips (2x 1x32bit 512kbit) ...

Or?

 

[Gubbi]

It depends on how you count the bandwidth. XDR uses differential signalling, so the x32 data bus actually needs 64 traces. That means a pair of 32-bit 3.6 GHz GDDR5 devices connected with the same number of data pads on the chip will give you the same bandwidth. That's been around for some time now, and I'm sure the best chips are even faster now.

Apples and oranges.

You need high quality power and ground planes to make common mode busses work. That requires a lot of extra pins.

Looking at Samsungs x16 XDR devices, all are packaged in 100 FBGAs, 20 of the 100 contacts are for power (VDD), 22 are for ground.

Their GDDR5 devices uses 170 FBGAs. There is no datasheet for GDDR5, but looking at the 136 FBGA x32 GDDR4 pinout, 30 of the 136 contacts are for power, 36 of the 136 contacts are for ground. And you have two power and ground planes, one for the data bus specifically. 22 of the 30 power pins are for this data power plane, 24 of the 36 ground pins are for data ground. This adds 46 pins specifically for improving power and ground plane quality for the data bus.

I'll bet the majority of the extra 34 pins required for GDDR5 are for additional power and ground plane quality.

Cheers

 

[Crossbar]

So just for keeping things clear, the PS3 has four XDR RAM chips now right (2x 2x16bit 512kbit)? And these could be consolidated into two XDR RAM chips (2x 1x32bit 1 Gbit) ...

See fix in bold. If that is what you meant, that is also my take on this.

And thanks Gubbi for your dive in the data sheets.