Print 8 comment(s) - last by Knish.. on Jun 14 at 8:50 PM

My thoughts on recent developer documents from Sony DevStation

Friend and colleague Charlie Demerjian just ran a series of articles detailing some of the hardware used in the development and production Sony Playstation 3.  However, it was Demerjian's piece on memory throughput on the Playstation 3 that sparked everyone's attention.  After having the opportunity to look at the document referenced in the article, I can reasonably confirm that what Demerjian has written is authentic. 

Here is a quick recap of what the DevStation document claims:
  • The original Sony PS3 development kits were configured with a South Bridge between the Cell processor and the RSX GPU. 
  • The RSX GPU has 256MB of local GDDR3 memory, and another 256MB of XDR memory accessible via the South Bridge.
  • The production PS3 systems no longer have a core logic bridge; instead the core logic is integrated onto the RSX package.
  • Cell's read access to the RSX local memory is extremely handicapped -- down to 16MBps.  The write access is still capable of 4GBps.
  • The document goes on to detail the RSX clock frequencies are set at 420MHz with a 550MHz target, and local memory is set at 600MHz with a 700MHz target. 
I will not dwell too much on the South Bridge issue.  With the original development kits, it seemed like it might be a nice feature to use portions of the RSX local GDDR3 to offset the Cell's XDR when needed.  This can still be done by using the RSX as a proxy, but in reality the sense that many applications would even need to read/write to the RSX memory seems unusual anyway.  After all, the whole intention of Cell's SPEs was that the CPU would thread application specific things and the GPU would be ... just a GPU.

The point that makes me irked is the GPU clock and memory speeds.  It was already well known that the RSX was going to be a glorified GeForce 7900 series with an extra trick or two.  Well, the extra trick seems to be the integrated Southbridge, which may help Sony's case in the long run as fewer chips equates to less cost.  550e/700m target clocks are similar to a GeForce 7900GTX.  When the XBOX (the original) launched, the graphics core was sort of a glorified GeForce 3 series GPU, but the whole system cost less than a high end GeForce 3 at the time.  Granted, computing hardware is much more mature than it was in 2001.

Launching with a GPU that is more or less a year old does have some advantages for Sony -- the Xenos GPU featured in the XBOX 360 was new territory for hardware/software developers.  Claiming PS3's 275M triangles per second will be the death of graphics on the PS3 seems like a bit of an overstatement.  I personally have never seen a game push more than 3M polys per frame, which calculates out to 180 triangles per second.  That's not to say the hardware shouldn't push 500M triangles per second as with the XBOX 360, it has to last a few years.

Overall, I suppose I expected a little bit more from SCEE, particularly with the majority of the hype in the direction that PS3 will offset many of the functions of a computer.  It is a high end computer for 2006 with regard to graphics, but expecting something revolutionary may have been setting the bar too high.

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Sony PS3 will bomb
By proamerica on 6/10/2006 12:31:13 AM , Rating: 2
Hand it to Microsoft, they blew Sony out of the water this time around. The PS3 looks like a nightmare, at least the press coverage of it looks that way. What else can be said, its not even half as powerful as the 360.

You can claim that its still "powerful enough", but only at a lower price-point than the 360. I think its a fair bet that the PS3 will be priced to high even if it was more powerful than the 360. Being half as powerful makes the expected price an absurd joke.

Good thing for Sony they can count on their loyal Japanese citizens to keep them profitable. Nothing like having a nation of willing conformists to keep your piece of shit console afloat...

Sony will rebound, they dominate in way too many industries to not rebound.

RE: Sony PS3 will bomb
By NuronV on 6/10/2006 4:39:08 AM , Rating: 2
Where are you getting this "its not even half as powerful as the 360" from?

I'm confused to why this references south bridges. I am coming from PC background so I might be wrong but wouldn't it be better just to say the dev kits had an seperate memory controller and now it has moved to a shoddy onboard one. South bridge to me means a IO Controller Hub and a north bridge means a Memory Controller Hub.

RE: Sony PS3 will bomb
By KristopherKubicki on 6/10/2006 6:07:39 AM , Rating: 2
On the development kits, the Cell used to interface to the RSX via a South Bridge. This South Bridge is gone and now the Cell just interfaces directly with the RSX. The memory controller for the GDDR memory has always been on the RSX, and access to the XDR memory has always been via the Cell.

Where are you getting this "its not even half as powerful as the 360" from?

The XBOX 360 can do twice as many triangles per second, so I suppose that is where he is getting that number. Frankly, I think Tri/s is sort of a BS number when it comes to computer hardware for the reason I stated above in the blog.

RE: Sony PS3 will bomb
By CrystalBay on 6/11/2006 10:07:24 AM , Rating: 2
So charlie did call it right. Quite a few peeps (fanboys) were saying he didn't know what he was talking about.
Major faux paux for Sony...

RE: Sony PS3 will bomb
By proamerica on 6/14/2006 3:14:39 PM , Rating: 2
I don't know what you mean by "BS number". Do you mean that its irrelevant, or that its one of those numbers that means nothing sort of like LCD response times?

I think most people will agree that while all parts of a computer have something to offer towards increasing overall performance, when it comes to graphics, the GRAPHICS CHIP, is probably the most important factor to look at.

RE: Sony PS3 will bomb
By Knish on 6/14/2006 8:50:50 PM , Rating: 2
I don't know what you mean by "BS number". Do you mean that its irrelevant, or that its one of those numbers that means nothing sort of like LCD response times?

Do 500M triangles a second make any difference when the typical signal is doing 100M tops? Not to mention the real-world correlation between Tri/sec rarely seems to equate to performance in real life applications anyway.

RE: Sony PS3 will bomb
By sxr7171 on 6/11/2006 5:50:44 PM , Rating: 2
Nah, stupid blind idiot fanboys will keep it alive. They did the PS2.

RE: Sony PS3 will bomb
By tuteja1986 on 6/12/2006 12:05:17 PM , Rating: 2
Ammm , Why the hell are paying $600 :?

Sony better not hopping that people buy craploads of music and game add threw their Network Hub station service to make their looses back. I would rather have a better GPU , more ram , CPU that is development friendly and Physic Processor than Blu-ray ;( . Also more games since the launch titles are crap and Sony got crap all until early 2008 when games like heavenly sword , MGS4 , FF13 and Devil May cry come out.

"Death Is Very Likely The Single Best Invention Of Life" -- Steve Jobs

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