Cell and RSX


CellBattling perceptions that the PS3’s RSX graphics chip is weaker than the 360’s Xenon, and that the Cell processor isn’t suited to games, a poster over at datafuse.net had some great insights to share.

For example, when the Xenon’s unified shader architecture was mentioned as superior to the RSX’s more traditional architecture:

Unified shaders do not necessarily provide any more power. It’s just a new way to arrange power. In terms of raw horsepower, RSX beats Xenos quite handily – floating point power is greater, shader ops are higher, it’s clocked faster, higher fillrate etc. Xenos’s claim to fame is that while it has less of a punch, it should be used more efficiently, but in a closed box such as a console, such concerns are somewhat mitigated since a dev can hunker down and get the best out of ANY chip. Xenos is also the first implementation of a new architecture – not always a good thing, and we’ve seen suggestions of some sacrifices on the part of devs.

And on the Cell processor, when people said it wasn’t suited to games:

Pure nonsense. This guy has obviously not been paying attention to IBM’s work with raytracing and rendering on Cell for example (or The Getaway demo which was apparently rendered only using Cell) and too much time reading Major Nelson-style ramblings. If you simply listen to what developers are saying they are using more CPU power for, Cell starts looking exceptionally suited for games. Most devs seem to be using extra cores for physics, animation, particle systems, graphics, audio, fluid/hair/cloth dynamics – these are the things which are most compute intensive, and these are the things the SPUs in Cell are really good at. As good, if not better than a conventional core, and there are 7 of them there in addition to the PPE. If you don’t believe me, look up Tim Sweeney’s comments about Cell on anandtech.com – basically he says that the things SPUs aren’t suited toward only take a small proportion of execution time anyway, and can be easily accomodated on the PPE. Or Crytek’s comments about potentially achieving a linear speedup across the SPUs. Cell is a clear and large advantage for PS3 when it comes to games, there’s no doubt in my mind.

Now of course you can throw a dart in a room full of gamers and hit 17 opinions, but I still like to see people standing up for the PS3 with all the 360 hype floating over the airwaves these days.

DataFuse.net – Sony PS3 Graphics, there’s more to it


Written by: Blackstaffer - News Contributor


  1. #1 by Black Guy on December 21st, 2005

    I find these kinds of “supporting” articles for either system rather amusing and they all reek of bias. The writers all claim to know somebody who works on this or that and that that somebody has intricate knowledge of the inner workings of both systems; how convenient. Claiming I know what Apple will release next because Steve Jobs and I drink at Starbucks every Thursday is just as absurd as these articles.

    If the writers aren’t doing the aformentioned, then they’re taking the technical knowledge thats available to everybody now, front like they’r some kind of technical expert, infect the information with their own biases, then inleash on the gullible masses.

    The PS3 may very well be faster than the X360. No surprise there since it is launching later and is generally expected to cost more. However, its not coming out that much later in the future, so I doubt that they’ll have that much of a technological edge. At least not enough to make a real difference. Most of the information sited in this article supporting the PS3 has been else where but in support of the X360. Clearly nobody really knows anything and we’ll have to judge for ourselves when the games start coming out.

    (This may contridicate the presvious parts of my post) There is an article on hardocp.com detailing the specifics of the unified architecture of the X360 GPU. According to the article, if the GPU is programmed correctly, it can execute 2 shader operations per cyle totaling 96 billion shader ops per second. Thats only 4 billion less than the claimed performance of the RSX in the PS3. If all this information is true, then like I’ve argued before, there is not going to be a night and day difference between these two systems. I think both are/will be great systems…. Its going to come down to the franchises you like to play and if u like to play online (Xbox Live).

  2. #2 by Henning on December 21st, 2005 [ 0 Points ]

    Of course. It’s all about the games.

    But that doesn’t mean people can’t talk about the hardware too. And it’s all in good fun. It’s not like anybody’s losing any sleep about this stuff. (I hope!)

  3. #3 by Black Guy on December 21st, 2005

    Henning:

    Some people do loose sleep. There posts out there that have death threats over this stuff.

  4. #4 by Hiro on December 21st, 2005

    Too much technical mumbo jumbo!

    While i don’t mind a bit of a bitch fight over tech specs that are completely pointless, i don’t really care. I do really wanna see the games this technology is going to pump out.

  5. #5 by aperson on December 22nd, 2005

    we can’t talk about games really…there is no games that the common person has played thats on the PS3 so we talk about what’s out there…simple as that

  6. #6 by crazzylee on December 22nd, 2005

    *** moderated ***

  7. #7 by Black Guy on December 22nd, 2005

    *** moderated ***

  8. #8 by Frost on December 26th, 2005

    Well Playsation well always be the best because of there games. Most of the people I know including myself have grown up with this game. (from the high school to college). And also I read offical news from gamespot.com saying that sony did not give the full specs of the PS3 (rsx and the cell chip) at E3 was because theydidn’t want people to get the wrong idea which some of you are getting now. The X360 Graphics card has like 22 pipelines, (thats a guess cant remember how much) and the RSX has like 24. One of the RSX’s pipelines are about 2-3 of the x360’s Graphics cards pipeline and so it is with some other specs from PS3. However thats one of the reasons they did give all of the spec on PS3.

    (I dont know if this is ture but I heard it on ign.com that the ceo of IGN had a talk with someone from sony, (Ithink it was ken) some time after the PS3 comes out there going luanch a space Satellite.)

  9. #9 by Vulgotha on December 23rd, 2006

    To the poster above, the Xenos GPU in the 360 has 48 pipelines, but each are half as “strong” (for lack of a better word) as the RSX’s. Thus a Unified Architecture like this whole story is about, is merely about tweaking each and every one of those pipelines into doing what you want them to do. This man is precisesly right, Unified Architecture is nothing more then Hype, the only thing that the Xenos has on the RSX is its 10 meg of edram.. THATS IT.

    RSX has more brute force though less “refined” but again, as the man said, Dev’s learn to tap most machines hardware given a year or two’s time at any rate… So i don’t see any real GPU stompage going on here on the 360’s behalf… what little there is the Cell makes up for it (as it can be used in similar aspects as a GPU), as the Xenon is a piss poor comparison to the Cell no matter what the 360boys may cry out (if it wasn’t you’d hear more devs’ talking about the 360 CPU, IBM talking about the CPU and etc, but nobody is talking about the Xenon A.K.A Waternoose (As IBM dubbed it) now are they?).

    Also, before any 360 fans want to scream out “360 has a 256 bit bus and the RSX has only a 128bit bus and double the ram for textures”… let me shoot that down before it even flies.
    1. RSX has two, I REPEAT TWO, 128bit buses. in addition it has Nvidia turbocache (which Xenos lacks) so it can nab XDR main Ram fast (WHICH RSX was allowed access to by the way). Faster then the 360 can nab its “unified memory”. Oh wait! so that means the PS3 can actually USE its 512mbs for textures and graphics? YEA… if you guys did the research and actually don’t buy into “Major Nelson” it can easily do all those things and more.
    The only kind of memory advantage the 360 has, is a 32 meg one. Its OS is 32 megs
    the PS3’s is 64. (NOT 96) Iwunazaki cleared that up in a recent interview about the PS3 OS. But most idiot sites that apparently don’t do any kind of research keep posting 96 cause’ the 360 bloggers all say so, so it must be so!

    Finally, the 256 XDR ram is clocked at 3.2Ghz (blazing Fast), XDR is inherently better then GDDR3 anyways, so it is a monster. XDR was designed to eliminate latency problems that plague other forms of RAM at high speeds so don’t shout that either, again do the research. The Deconstruction of the PS3’s hardware and building up of the 360’s hardware is PURE crap from Microsofts camp. Its understandeable that you bought the 360 a year earlier and can’t buy a PS3, and thusly you have an invested interest in the 360’s success Halo 3, etc… But don’t try and lie about a console, it just won’t fly.

  10. #10 by ANDYtt on January 30th, 2007

    if u also did TOUR research you would realize that the RAMS latencies problems have been eliminated but………….OH WEIT!….the RSX cannot handle those latencies so WATS THE POINT ANYWAYS?….so its a wast…I MEAN I GTTA GIVE IT TO SONY THEY HAD SOME NICE IDEAS>..buuuuuuuuuT I REALLY think it will be hard for them this time round….!

  11. #11 by ADX on December 21st, 2007

    Architectures in the CPU and the GPU are at a crossroads now. GPU’s are currently the fastest commodity processors made compared to CPU’s. The GPU’s can now run general program code, which developers are now using the GPU’s expansinve pipeline resourses and high transitor count.

    The CPU’s are now in the phase of expanding execution cores and focusing less on pipelineing. The CPU’s still have fewer transitors compared to GPU’s.

    The CELL/RSX implementation in the PS3 tries to improve on CPU usage instead of the GPU route that the entire indusrty has been moving toward the last decade, which I think is a mistake.

    The XBOX 360’s Xenos GPU is essentially the northbrige with direct access to the system memory. The unifide pipelines take full advantage of GPU resourses. This is a new kind of GPU design with general purpose processing capabilites that we have not seen before in GPU’s. In the XBOX 360, the 3 core CPU is dwarfed by the GPU and is simply used for AI and game code execution.

    The CELL is a new CPU design that tries to increase floating point calculations, which has been dominated by GPU’s. While this is essencially an attempt to beef up the CPU’s role in high end floating point calucaltions and vector math, this cutts into the transcending GPU technology, which is still more powerfull than any CPU including the CELL.

    The Problem with the PS3’s CELL/RSX is that the RSX is a traditional GPU that relies on the CELLs vector DSP units for vector math and vertex shader program execution. This eats up processor to processor bandwith for tasks that can be handled on a single GPU anyway. Remember that GPU’s are more powerful than CPU’s.

    The RSX does not have a unified pipeline so inorder to increase vertex performance, the RSX must offload to the CELL. On paper, Sony just added the incresed capability of vertex shading with the CELL, but that increase the number is not an avantageous increase in performance.

    The 360’s Xenos does not offload to the CPU for vertex programs, but simply makes the enire GPU avalilble for massive vertex processing, thus taking advantage of GPU strides.

    The CELL/RSX is not a good implentation for 3D games as more vertex operations are being used by game developers with less pixel operations. The bottleneck that occurs in the PS3 in the expansion of vertex operations will be limiting.

    To add to that, the segragated memory in the PS3 (256MB for CELL/ 256MB for RSX) will make memory usage inefficient. The CELL’s memory is accessable to the RSX, but again, this will cut into processing bandwidth even further.

    The Load times on the PS3 will suffer because of long program code due to the 7 DPS’s and the fact that there is only one general purpose unit in the CELL, and that there is only a 256MB storage space for the code. That means heavy compression, longer load timed, less quality texture processing. The 256MB for the RSX will almost be dedicated to texures because of this, and less memory will be available for shader programs.

    Conclusion is that GPU’s will dominate over CPU’s as GPU’s become more generalized processors.

  12. #12 by Metroid rules! on February 9th, 2008

    Im not here to bag the PS3, its a great machine, but the fact is the Xbox 360 is MORE than the PS3. The RSX can perform 5 shader ALU ops per cycle for its each of its 24 pixel shader piplines and 2 for its each of its 8 vertex shader piplines, which equates to 74.8 billion shader ops per second ((24x2x550)+(2x8x550)), where as the Xenos has 48 piplines, each capable of pixel of vertex shader operations, and that each pipline is capable of 4 shader ALU ops per cycle so its capable of 96 billion shader ops per second (48x4x500). Also because the Xenos has Unified shader Architecture it CAN do all 96 billion shader ops per second, but the PS3 GPU usually only performs at about 70% efficiency. Tens thes the smart RAM for the Xenos which can do free x4 AA (no work load on the parent GPU), and good Z stenciled shadows (Doom and Prey like shadows). And its Unifide memory Architecture runs at 700 mHz, and has a large bandwidth, lager than the XDRs and the RAM on the RSX.
    Finally the Cell, it may be good at doing graphics (for a CPU that is) but it is crap for AI and not much better than normal CPUs for physics, in fact the Xenon (360s CPU) is much better than the Cell at doing AI.
    I think I’ve said enough, but to say one last thing I have a Wii, one of my other friends has a PS3 and another a Xbox 360, my friend who has a PS3 went to my friend who has a 360s house and when he saw Gears of War he said, “That looks like the killzone 2 pre-render videos!” and I had seen them too and had to agree.


You must be logged in to post a comment.

Like trophies? Like giveaways? Want to speak your mind? Register here!