Xbox 360: First Look at Final Hardware

[Erzengel]

I don't know why this is being discussed as if the article was fact when everyone knows its not.

I mean here's a German's response ont his.

Hi, thats me Forget all their technical explanations regarding the Xbox360. In the past this was a really good IT site, but now they are totally against everything from Microsoft but Linux. They (the author) were the first which claimed that the Xbox360 can't handle FSAA for free and also links from me to Daves Article produced no attention to him. He said many times that the Xenos is an old middle class GPU and so on. Really worse journalism.

Sorry for my bad english.

Greets Erzengel

 

[Acert93]

I'm not going to dismiss an article because some body who seems by that post to be quite baised himself says the site is biased.

Besides the magazine being biased (making conclusions about hardware that is not on the market and no pricing details?) there is a pic in this thread indicates the poster is correct.

1. MS announced 1080i support at E3
2. Supposed MS employee notes 1080i is supported
3. Dashboard picture appears to corroberate the "employee"

Its not like I am outright dismissing them. The problem is that there is a lot of counter evidence and they are introducing information that contradicts MS's public stance--not to mention screen shots of the dashboard.

Maybe the demo they saw did not have 1080i, but drawing significant conclusions, from non-final hardware, that contradict MS press releases and product shots seems to be jumping the gun.

It may turn out 1080i is not on the dashboard for whatever reason. But so far it is his word against MS's and pics of the dashboard. Until we hear otherwise from MS or the final hardware hits the market notes likewise I will tend to be skeptical about this claim.

ERP on the other hand... he has a lot more direct information about the product and how it will ship and how it actually works. You are not going to find many people on the internet who know more about the Xbox 360 or PS3 than ERP.

Safe to say his opinion is founded in hard facts direct from the source.

Global illumination on Xenos?!?!

It is not a "feature". It may be something you could attempt to do with the hardware in general (I am not sure it is powerful enough), but it is not a "features" of Xenos. The "fan" is talking is confusing features with design models. I highly doubt we will see any "global illumination" -- at least in the sense of what offline renderers use.

 

[ecliptic]

I have no problem dismissing the site.

But ERP is knowledgable and very trustworthy--he is a developer working with the hardware. His comments are interesting, constructive, and quite instructive on the current state of affairs.

It will be interesting to see how this plays out at launch and, more importantly, in the next 6 months as devs actually get a handle on the hardware.

element is an MS employee who specifically stated 2x AA is required and he can select 1080i on his dashboard.

 

[Acert93]

element is an MS employee who specifically stated 2x AA is required and he can select 1080i on his dashboard.

But how do you know he is a MS employee? If you do, cool, but I don't trust many on the net. I know MS employees myself--but none in the games division Unless he has had some credentials connecting himself with the Xbox projects I would be skeptical. But you could be right (what he is saying is inline with what MS has on their site and stated at E3).

DeanoC, ERP, Faf, Panajev, nAo, etc are known devs here on B3D. This has been verified and can be verified.

They (the author) were the first which claimed that the Xbox360 can't handle FSAA for free and also links from me to Daves Article produced no attention to him. He said many times that the Xenos is an old middle class GPU and so on. Really worse journalism.

2x MSAA may be "relatively free" but 4x MSAA is a 1-5% hit in performance. Those are ATIs numbers.

But if we are to take ERPs words as a summary of the current state of actual implimentation by some devs (not all mind you), it does appear that there are some hurdles and it could be difficult for devs who have been working with the hardware for only a couple months to reach those figures.

The joys of a new architecture and a crunched launch date. Yay

 

[Erzengel]

It is not a "feature". It may be something you could attempt to do with the hardware in general (I am not sure it is powerful enough), but it is not a "features" of Xenos. The "fan" is talking is confusing features with design models. I highly doubt we will see any "global illumination" -- at least in the sense of what offline renderers use.

I am not a fan. I just read this in many articles that the GPU can handle this. In which way i don't know, also i don't know whats the impact on the rest of the system. By the way, i think Bizarre Creations said that Project Gotham Racing 3 uses Global Illumination. If GI inthe Xbox360 is only a small subset of the whole i don't know. Please take in mind that my englisch is not the best and looks like a ****** post. Most of my posts are really basic and short. I am not saying that such features come with a no-hit to the rest of the system. I think nobody knows until the games designers are telling us.

I just wanted to show that the author mentions always (in my words) features of the RSX and on the other hand he won't mention and explain the things in Xenos. Thats all i wanted to say about this.

I'm not going to dismiss an article because some body who seems by that post to be quite baised himself says the site is biased.

I am not biased, really. ATI/NVidia or Microsoft/Linux is not my war. I just wrote this cause i know that the site is now a pool just for everything against Microsoft and the articles particularly the ones from this author are technically 50% wrong as what i get from Daves Article and other sites like Arstechnica, Anandtech and so on.

I don't know why he always bashes everything regarding the Xbox360, maybe he is an trainee? I don't know.

 

[Lysander]

Yes, global ilumination is possible based on
hardocp

 

[ecliptic]

But how do you know he is a MS employee? If you do, cool, but I don't trust many on the net. I know MS employees myself--but none in the games division Unless he has had some credentials connecting himself with the Xbox projects I would be skeptical. But you could be right (what he is saying is inline with what MS has on their site and stated at E3).

DeanoC, ERP, Faf, Panajev, nAo, etc are known devs here on B3D. This has been verified and can be verified.

Because everyone knows who he is. He has been around there for years and many have met him personally..

 

[Erzengel]

@Acert93: Okay maybe 4xFSAA was the wrong thing i wrote, you are right

PS: pls don't think i am just a fan of something. I'm not a gamedeveloper but working for nearly 20 years as a system developer and I'm very interested in new technology. Thats all.

 

[Acert93]

Yes, global ilumination is possible based on
hardocp

Some of the global illumination effects you might have seen in years past at SIGGRAPH have been put into motion on the Xbox 360 GPU in real time. For the most part, global illumination is necessary to render a real world picture quality 3D scene. The Xbox 360 also makes using curved surfaces possible in-game, meaning that it can calculate the polygons from the proper curved surface math in order to draw it on your screen “correctly.â€￾ Much in line with this is the ability to do high order surface deformation. Moreover, if you are familiar with high order surfaces, you are likely familiar with what gamers and hardware enthusiasts commonly refer to as “LODâ€￾ or Level of Detail. Mr. Feldstein shared with us that the Xbox 360 GPU has some “really novel LOD schemes.â€￾ Therefore, it appears as if the days of pentagonal shaped wheels on the cars in the distance in new Grand Theft Auto titles is a thing of the past.

You are right, I am wrong. Thanks man Although I will note that this is in theory; will it make it into games? Honest question. I know that GI has been discussed with in regards to CELL but the concensus has been "probably not, at least not to the detail we see in offline renderers".

It will be exciting to see though what happens. Devs FREQUENTLY shock us with what they can do!

@Acert93: Okay maybe 4xFSAA was the wrong thing i wrote, you are right

PS: pls don't think i am just a fan of something. I'm not a gamedeveloper but working for nearly 20 years as a system developer and I'm very interested in new technology. Thats all.

Nothing personal Erzengel, we just get a lot of new guys here frequently talking out their arse.

I was being abrasive because we get a lot of people saying, "Xenos can do this" and "RSX can do that" type stuff and start a lot of meaningly hardware wars.

Xenos and the eDRAM seem to be pretty powerful--but a lot of people have played it down very hard on these forums, and a some have overplayed it. I am sure most of us have had enough of the bull. We should count the positives but not downplay the negatives.

That is not directed at you though. You were not part of those debates and it seems you are an enthusiest just like me who wants to enjoy this stuff. No harm in that.

Welcome to the forums and I apologize for jumping down your throat. Nothing personal... just trying to keep this thread in order. We had a nice troll outbreak this morning, so we really don't need much more of that.

 

[blakjedi]

EDIT: Acert beat me to it!

 

[Erzengel]

No Prob, i can understand that

 

[expletive]

Ok so are well copacetic back in EDRAM land or is there still something up for debate?

J

 

[s1lverbak]

The article said they hooked it up to a PC Monitor right? Than no 1080i would be correct, because, as far as I know, PC Monitors cant display 1080i...maybe 1080p?????????

 

[one]

I think this are all the same res pictures (in original); different websites just posted them in different format; same happened with ghost recon.

It doesn't look like a coincidence as by using the resolution you can avoid tiling even with 2xAA as ERP suggests. And jaggies seen in 720p.

 

[Titanio]

Is that FP16 mode that 360 use's any good compared to the other version???

I would say most games that are currently using HDR on X360 are using FP10..

FP16 would double your color buffer size, and thus perhaps double your tiling.

edit - it actually wouldn't double your tiling at 2xAA at least, but would require 3 tiles. Unfortunately 720p, FP16 with 2xAA (and a 32bit zbuffer) comes in at just over 21MB. With 4xMSAA, you'd require 5 tiles.

2x MSAA may be "relatively free" but 4x MSAA is a 1-5% hit in performance. Those are ATIs numbers.

Dave's article talks about 4xMSAA being 95% of the performance of 2xMSAA, but doesn't mention the hit for 2xMSAA. I'm also wondering what that claimed hit refers to - the computational cost on the daughter die logic, the tiling cost, or both.

Re. "global illumination", such is possible on any SM3.0 card, or at least hacks that would be labelled such for PR purposes

Xenos seems like a more complicated GPU to develop for than RSX, and it's certainly an architecture developers haven't had a chance to use before, so there's bound to be a learning curve as ERP suggested.

ERP can correct me if I'm wrong here, but I'm not sure how much scope there is for changing behaviour on the eDram side. It should be a matter of toggling between resolutions, colour depths, AA etc. to find what works? For other effects with more programmability (DOF,motion blur etc?) there may be room for optimisation, but I think it might be as much a question of changing things elsewhere or planning things overall from the start to accomodate such things.

 

[_phil_]

I am not a fan. I just read this in many articles that the GPU can handle this. In which way i don't know, also i don't know whats the impact on the rest of the system. By the way, i think Bizarre Creations said that Project Gotham Racing 3 uses Global Illumination.

yes ,like any modern gpu can do that .you can use that kind of global illumination that way on a ps2 or a xbox ,btw.it's called baking offline final gathering onto the vertices ( or lightmaps ).
Static prebaked stuff.(from mentalray ,for example )

As for the other stuff ,any recent gpu can do raytracing ,IBL, caustics,photon mapping ,radiosity.The only question is at what framerate ?
Most are not possible in game.

 

[[maven]]

There are about 3 reasons I can think of for the 1080i situation:
- Incorrect information (in the article or in the fact-sheet)
- Difference European / American models (but I thought this had come to an end)
- Difference Devkit / Consumer Hardware.

I think ERP hit the nail on the head, 2xAA is for free - except for the memory overhead in the EDRAM, which requires the developer to have gotten up to speed with the tiled rendering approach implemented by Xenos, and launch games may simply not have had that "luxury".

If if Microsoft have a choice between a launch game without AA or no launch game with AA, I am quite confident I know which one they'll pick.

And Erzengel, I disagree with your opinion on Heise (which certainly was true about 2 years ago); but even then that would only taint their conclusion. Would you recommend a 400 Euro package to a casual gamer (which is what they're addressing) on the strength of a single game (Kameo) given the DRM and other restrictions?

 

[Laa-Yosh]

Global illumination is actually a collective noun, and there are many different techniques to implement it. I've once read a detailed explanation of the proper terminologies and stuff, but mostly forgotten it in the past years

 

[Titanio]

I think ERP hit the nail on the head, 2xAA is for free - except for the memory overhead in the EDRAM, which requires the developer to have gotten up to speed with the tiled rendering approach implemented by Xenos, and launch games may simply not have had that "luxury".

There's more than the cost of bandwidth in the eDram, which let's face it, isn't really a cost since there's so much of it there (up to a point anyway).

The costs as far as I can see fall under a few different headings:

1) Computational cost on the daughter die, whatever it might be - intuitively, it seems to make sense that not doing any AA will be faster than doing 2xAA, and 2xAA will be faster than 4xAA.

2) Bandwidth cost on the daughter die - but again, there's so much of it there.

These are "normal" costs associated with any GPU's framebuffer. However with the eDram, and with anything from a 720p 32-bit frame with 2xAA upwards, there'll be tiling costs, which as far as I can make out, invoke further costs as per the previous conversation:

3) Some duplicate processing for polygons intersecting the division between one tile and another (those polys get processed to a point for both tiles)

4) Maintenance of display lists (large?), having the command processor checking commands that it may not be able to run etc.

5) GPU idle time during edram->memory copy of colour buffer (?)

6) A little consumption of main memory bandwidth. I figure on the lower end, FP10 720p at 30fps = 210 MB/s (or 1% of main memory bandwidth) to a higher end, FP16 1080i at 60fps = 712 MB/s. (or 3% of main memory bandwidth). If you don't have to write out the z-buffer too, that drops to 105MB/s (0.5%) on the low end and 475 MB/s (just over 2%) on the high end

(The last point may apply whether you are tiling or not, Dave's article mentions that "in some cases" the buffer can be sent straight to the DACs, I'm guessing perhaps if you aren't tiling that may be possible)

My question is what the performance costs we've seen claimed account for - all of this, or just some? Some of the above things are going to be very variable, even frame-to-frame.

edit - regarding other "effects", is it not correct that things like DOF, motion blur etc. are "done" on the parent die, in shaders? If that's the case, the daughter-die costs associated with those, then, would be fillrate and bw related, which suggests to me that the AA/tiling is more the issue. May well be wrong though..

 

[Nemo80]

Well, since PGR3 Devs said that they will go for 720p alongside with 2xAA only, and also 640x480 with 4xAA i would assume that AA "for free" is nothing but M$ marketing bullshit once again (especially since NFSMW devs have the same problems with AA).