Why's XDRAM so slow?

[Vaan]

Sony has great plans on cell, so they needed to fix an scalable memory solution. XDR provides much more permormance expectance on the long term, avoiding sony to change cell's memory interface.

They also patched the console with RSX

 

[phat]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

Umm... no.

 

[phat]

So the consesus is Sony missed the boat this time around? They were aiming for for something they couldn't manage, so went for a best compromise, taking nVidia's expertise at the cost of needing a different memory type, and going with XDR despite its cost for the low latency?

Ideally, they would have liked a unified 512 mb XDR?

The Cell + XDR and RSX + GDDR3 combo does seem a bit like a duct-tape job. But that doesn't mean it can't be as good as a full XDR solution. The bandwidth is nearly all there. It's just that I think the PS3 is going to be more expensive for Sony to produce than they had planned. They're going to try to pass on that cost to us gamers somehow...

 

[PC-Engine]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

Umm... no.

The Cell + XDR and RSX + GDDR3 combo does seem a bit like a duct-tape job.

 

[Acert93]

The Cell + XDR and RSX + GDDR3 combo does seem a bit like a duct-tape job. But that doesn't mean it can't be as good as a full XDR solution. The bandwidth is nearly all there.

Exactly. Actually, this design should be cheaper. Why use the low latency XDR for the GPU when cheaper GDDR3 is sufficient? Not a bad tradeoff.

It's just that I think the PS3 is going to be more expensive for Sony to produce than they had planned. They're going to try to pass on that cost to us gamers somehow...

That is going to be the interesting part

 

[lip2lip]

will the ram need to be water cooled like the rest of the system? anyone?

 

[j^aws]

XDR controllers are 32-bits wide each, and CELL has two of them. Each 512 Mbit DRAM is 16x (16-bits wide), so there's a total of four for 256 MB.

64 bits * 3.2 GT/s = 25.6 GB/s. Also, it does suggest that the DRAM clock for these chips is at 400 MHz. Perfectly normal for soldered-in DRAMs.

Yeah...700 MHz GDDR3 (1400MHz effective, 128bit) and 400 MHz XDR (3200MHz effective, 64bit)...

 

[phat]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

Umm... no.

The Cell + XDR and RSX + GDDR3 combo does seem a bit like a duct-tape job.

I wasn't disagreeing with you about the "last minute bolt-on" theory. I was disagreeing that the dual HDMI outputs have anything to do with it. They're perfectly consistent with Sony's aggressive connections/format coverage. It's clear that Sony is not just paying lip service to this living room hub concept, as it's certainly not cheap to include all those connectors and support all those memory card formats.

 

[PC-Engine]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

Umm... no.

The Cell + XDR and RSX + GDDR3 combo does seem a bit like a duct-tape job.

I wasn't disagreeing with you about the "last minute bolt-on" theory. I was disagreeing that the dual HDMI outputs have anything to do with it. They're perfectly consistent with Sony's aggressive connections/format coverage. It's clear that Sony is not just paying lip service to this living room hub concept, as it's certainly not cheap to include all those connectors and support all those memory card formats.

Fair enough.

 

[Panajev2001a]

The non-uniform memory system seems to imply that the switch to nivida happend quite late. This will probably have implications on their abilities to reduce manufacturing costs on further revisions

I disagree Pinky, I do not see why this would be true: once again they are in control of manufacturing and have been working quite hard with nVIDIA (nVIDIA assigned a team of is own engineers to work with Sony almost as a Sony team) on the GPU so they should be able to port the design (with their partners) to 65 nm and 45 nm technologies in the upcoming years.

 

[Guden Oden]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

I don't see how you can make that conclusion, just for starters, you have no idea of the capabilities of the original GPU that would have gone into the system if Nvidia hadn't been involved.

You're just crapping on sony at every chance you get, as per usual...

 

[London Geezer]

The point is, even if it's a bolt-on last minute job, ultimately, if this last minute change is faster than what was there before, who freaking cares!!! Some people will never stop nagging.

 

[Shifty Geezer]

Dual outputs still requires transistors and components it'd be cheaper not to have. Seeing as Sony are fabbing the chips why would they go with a function they don't expect to be used, just because it was already there? They have been working on this chip for months, if not years (details on the partnership are sketchy), it's not finished, and I doubt they'd include anything they didn't want. Also it's ATI saying it's a bolt on part. Do you really trust ATI to give unbiased opinions on their competitors products?

I doubt dual outputs will be used, but maybe Sony are appealing to the hardcore gamer with this option? One more string to their bow? I don't for one minute believe that they took an off-the-shelf G70 reference design, stuck it in PS3, and made no customisations at all. And if they have customised it, they wouldn't leave anything in they didn't want.

 

[PC-Engine]

Dual outputs on the RSX also support this last minute bolt-on PC G70 theory.

I don't see how you can make that conclusion, just for starters, you have no idea of the capabilities of the original GPU that would have gone into the system if Nvidia hadn't been involved.

You're just crapping on sony at every chance you get, as per usual...

If the orginal GPU design was up to snuff, they wouldn't have needed to go with a last minute PC GPU bolt-on.

 

[Shifty Geezer]

True, but how do you explain it was a last-tminute bolt-on when it happened like years before the PS3 is to be released? Sony tried 3 different approaches it seems, and the best approach it seems was to go with a leader in the field with lots of experience and a back catalogue of support tools that the other solutions couldn't offer.

 

[Mulciber]

does anyone have any real prices for XDR vs GDDR3? seems like everyone is just assuming XDR is going to cost more.

 

[PC-Engine]

True, but how do you explain it was a last-tminute bolt-on when it happened like years before the PS3 is to be released? Sony tried 3 different approaches it seems, and the best approach it seems was to go with a leader in the field with lots of experience and a back catalogue of support tools that the other solutions couldn't offer.

Press releases isn't proof it happened years ago.

RSX is basically a PC chip bolted on at the last minute.

 

[j^aws]

True, but how do you explain it was a last-tminute bolt-on when it happened like years before the PS3 is to be released? Sony tried 3 different approaches it seems, and the best approach it seems was to go with a leader in the field with lots of experience and a back catalogue of support tools that the other solutions couldn't offer.

Press releases isn't proof it happened years ago.

RSX is basically a PC chip bolted on at the last minute.

Yep, and the R500 is a PC chip bolted onto the X360...point?

 

[PC-Engine]

True, but how do you explain it was a last-tminute bolt-on when it happened like years before the PS3 is to be released? Sony tried 3 different approaches it seems, and the best approach it seems was to go with a leader in the field with lots of experience and a back catalogue of support tools that the other solutions couldn't offer.

Press releases isn't proof it happened years ago.

RSX is basically a PC chip bolted on at the last minute.

Yep, and the R500 is a PC chip bolted onto the X360...point?

Xenos is not a PC chip. It has a EDRAM block.

 

[j^aws]

True, but how do you explain it was a last-tminute bolt-on when it happened like years before the PS3 is to be released? Sony tried 3 different approaches it seems, and the best approach it seems was to go with a leader in the field with lots of experience and a back catalogue of support tools that the other solutions couldn't offer.

Press releases isn't proof it happened years ago.

RSX is basically a PC chip bolted on at the last minute.

Yep, and the R500 is a PC chip bolted onto the X360...point?

Xenos is not a PC chip. It has a EDRAM block.

Who cares if there's an EDRAM block, there just transistors devoted to storage and compression...point?