Could a console manufacturer switch to a different ram spec?

[Squilliam]

I was just curious, lets say Microsoft decided that GDDR3 + a 128 bit bus was getting too expensive, could they switch to GDD5 for example if the net result to the developer in terms of latency and bandwidth available was the same?

If they could do it, would it ever make sense? Could they ever get pad limited in their design theoretically?

 

[Brad Grenz]

No.

 

[3dcgi]

In order to switch technologies Microsoft would need to ensure performance is identical to the original technology. If possible, implementing and verifying this would be costly and timing consuming which would likely remove any benefit from lower prices for the new technology.

 

[Dominik D]

Not identical: not worse than. Faster, lower latency or whatever (as long as better) RAM wouldn't hurt the console.

 

[Squilliam]

Thanks, its nice to know this piece of info.

Lets say they had the console nice and shrunk down, and they were looking at producing and selling another 30 Million consoles at the lowest price possible, say after the nextbox is released. Would it make sense then to revise the console to use different ram based off the potential savings of using a smaller/simpler PCB and fewer ram modules?

 

[3dcgi]

Thanks, its nice to know this piece of info.

Lets say they had the console nice and shrunk down, and they were looking at producing and selling another 30 Million consoles at the lowest price possible, say after the nextbox is released. Would it make sense then to revise the console to use different ram based off the potential savings of using a smaller/simpler PCB and fewer ram modules?

Someone would have to know detailed costs in order to determine this, but another variable in the equation is AMD. Even though Microsoft owns the IP to Xenos it didn't design it and thus it will take them much longer to modify the memory controller to support GDDR5 than it would AMD's engineers.

It might not make sense for AMD to reallocate the necessary engineers for anything but a lot of money and the longer the redesign takes the less it makes sense. If it ever made sense.

 

[Carl B]

The chip would require a redesign. There's nothing ruling it out, but I don't think it would occur in a void. If/when MS combines the CPU and GPU outright, that might be an opportune moment to re-address the memory controller situation, as other significant redesign work will be taking place in tandem.

 

[fehu]

What about the possibility of 64bit bus with faster low latency GDDR5 to decrease cost?
Of course this is a job for amd.

 

[Brad Grenz]

There's very little incentive to re-engineer the memory controller just to use a more expensive kind of RAM.

 

[Carl B]

There's very little incentive to re-engineer the memory controller just to use a more expensive kind of RAM.

The incentive is the use of fewer individual RAM devices, which would lower board complexity as well. The RAM is only more expensive in relative terms; a couple of years from now, GDDR3 may very well be more expensive than the modern day equivalent simply due to the direction the fabs have taken. Think DDR pricing relative to DDR2 pricing right now at this very moment.

 

[Brad Grenz]

Well, I doubt the 360's lifespan is long enough to ever make this fanciful speculation cost effective.

 

[Crossbar]

Can the GDDR3 DRAM be replaced by DDR3 in the current gen consoles?

I´ve noticed that the GDDR3 memory is commonly replaced by DDR3 memory in economy to mid range graphics card. In the high end cards the lightning fast GDDR5 is starting to gain ground.

The adoption of DDR3 of intel for their new range of CPUs (core i7) and AMD on their way means that the price of DDR3 is heading for the DDR2 price range, so it makes perfect sense for graphics cards manufacturers to make this move.

The 360, PS3 and Wii all use GDDR3 700 MHz memories. If graphic card manufacturers abandon GDDR3 in favor of DDR3 and GDDR5, GDDR3 is at risk being left as a niche memory for consoles with a relative high price.

From a layman perspective a DDR3 at 800 MHz seems to offer similar or better data transfer rates as the GDDR3 at 700 MHz. Does anyone know if there are any specific characterisitcs of the GDDR3 DRAM that would hinder the console manufacturers to modify their memory controllers to support DDR3-1600 memory instead and save a few pennys?

 

[AlNom]

Moved your post here, Crossbar.

 

[Crossbar]

Moved your post here, Crossbar.

Thanks, it makes sense.

 

[Cheezdoodles]

From a layman perspective a DDR3 at 800 MHz seems to offer similar or better data transfer rates as the GDDR3 at 700 MHz. Does anyone know if there are any specific characterisitcs of the GDDR3 DRAM that would hinder the console manufacturers to modify their memory controllers to support DDR3-1600 memory instead and save a few pennys?

Dont think there is any specific characteristic that would be a hinder, AFAIK GDDR3 is just a modified DDR2 with new memory modules and cooling. I think DDR3 can do everything GDDR3 can do.

 

[Carl B]

Yeah switching to DDR3 would be fine down the line; again it's just going to be a matter of making some changes to the memory controller, which would probably occur around the same time as a larger concurrent shift... maybe at 45nm or something. Or, maybe the engineering hassles won't seem worth it, it's hard to say. If I was either MS or Sony, I sure wouldn't been working to secure some long-term, high-volume GDDR3 contracts in the last couple of months in the darkest days of the RAM industry.

 

[Kaotik]

Dont think there is any specific characteristic that would be a hinder, AFAIK GDDR3 is just a modified DDR2 with new memory modules and cooling. I think DDR3 can do everything GDDR3 can do.

There's a bit more than just that between DDR2 & GDDR3, but indeed GDDR3 is based on DDR2, not 3

 

[Crossbar]

Yeah switching to DDR3 would be fine down the line; again it's just going to be a matter of making some changes to the memory controller, which would probably occur around the same time as a larger concurrent shift... maybe at 45nm or something. Or, maybe the engineering hassles won't seem worth it, it's hard to say.

Switching memory technology when moving to a smaller process definitely makes sense and I think the cost save is pretty significant so I am sure the incentive is there if there is no drawback. Possibly in MSs Valhalla component when it appears if MS goes this route. Sony seems to have a two year cycle for their components, as the 65 nm RSX appeared last fall we could possibly expect DDR3 to appear in PS3 SKUs in the fall of 2010.

I just noticed that the frequency of DDR3-1333 (667 MHz) is very close to the current clocking of the PS3s GDDR3 (650 MHz). Could this possibly be the reason for down-clocking the memory? To get away with a cheaper DDR3 memory when/if they change memory controller? There you go, another theory explaining the weird down-clocking. :smile: (just another one, nothing more)

Edit: After checking the price difference between 667 MHz and 800 MHz DDR2 SDRAM I´ll scrap this theory right away.

 

[fehu]

DSi done it, so yes, it's possible

 

[Crossbar]

I have had second thoughts about my theory about GDDR3 memory being replaced by DDR3 in consoles.

That DDR3 is going to be used in graphic cards seem to be a common understanding.
I found these in a brochure from Qimonda.

However DDR3 memory is only offered with 4, 8 and 16 bit data paths, which makes it a bit awkward as a replacement for the GDDR3 chips with a 32 bit data path.

Especially since there is no 256 Mbit DDR3 memory and hardly any 512 Mbit modules as well. 1Gbit DDR3 seems to become the common low end standard.

This means that if we are to replace GDDR3 memory with currently available DDR3 memory it will mean they will at least double the memory size.
The benfit of doubling or quadrupling the memory of current gen console from a software point can be discussed, but I leave that for a different thread.
Let us look at it stricly from a hardware cost reduction perspective and look at the PS3 specifically.

Samsung 512 MBit GDDR3 memory units are used with the current 65 nm RSX core.

Spec sheet:

VDD 1.8 V
Max TDi 4 W
Data path: 32 bit
package: 136 ball FBGA,
Dimensions: 11 x 14 mm

DDR3
If we stay with Samsung and look at their DDR3 offerings, they only offer 1 Gbit DDR3 units and above in mass production:
http://www.samsung.com/global/business/semiconductor/productList.do?fmly_id=103

Spec sheet:

VDD 1.5 V
Max TDi 1 W
Data path: 16 bit
package: 100 ball FBGA
Dimensions: 9 x 13 mm

It seems like it would be feasible to fit 8 1Mbit DDR3 units together with a shrinked 45 nm RSX core within the size of the current substrate and stay within the current power envelope, probably lower.
I don´t know why the RSX has this current substrate solution, perhaps some hw engineer can fill me in. Maybe the separate substrate solution will go a away in the future and the RSX core and the memory units will soldered straight on the main PCB.

I have not been able to find any current price indication of GDDR3 memory, but the cost of DDR3 memory can be found here . I wouldn´t be surprised if GDDR3 memory units are more costly than current DDR3 memory. Anyway if not, within a year it will probably be the case, possibly below half the price, as DDR3 will grow in market share.

It should be noted that the price table doesn´t offer prices for 800 MHz DDR3 memory. I previously dismissed the possible connection between the current downclock of the PS3 GDDR3 memory (650 MHz) and the DDR3 667 MHz standard. I dismissed it because I thought the price difference would be insignificant in the long run, but there maybe more to it. The 667 MHz units may have greater availability and be able to work at a lower voltage than higher speeds units.

The DDR3L standard memory units will probably be available in the lower frequency range. However, that memory might be aimed and notebooks and carry a premium price and the current power draw of the 1.5 V DDR3 is already significantly lower than GDDR3.

Would it make sense doubling or quadrupling the memory size as a cost reduction? I think it might, but I am not totally convinced yet, any thoughts?