RSX: memory bottlenecks?

[London Geezer]

First I'm all about NAO32, but with that said since I imagine the RSX will most likely derive from the G71 rather than the G70, G71 is rumored to improve NVidia's AA performance, and will supposedly allow for both HDR and MSAA at the same time. So NAO32 aside, I still think HDR and AA will be possible concurrently via RSX.

Even then, the word is that NAO32 is much faster than FP HDR, so in the end, even if you can use FP + MSAA in RSX, devs might just want to use NAO32 as it's faster.

Guess we'll have to wait and see. Personally, when i'm there playing the game, i'll hardly give a damn about bloody FP and FX, as long as HDR is there and everything looks good...

 

[Carl B]

Even then, the word is that NAO32 is much faster than FP HDR, so in the end, even if you can use FP + MSAA in RSX, devs might just want to use NAO32 as it's faster.

Hey like I said, I'm all about NAO32.

 

[London Geezer]

Hey like I said, I'm all about NAO32.

The italians are creeping in!! One day all games will be made in Italy!
Fiat and Ferrari will be battling it out with their own consoles!!!

 

[pegisys]

I think it still depends on what you want the game to do, I haven't keep up with NAO32 but from what what said before, it lowers pixel shader performance, if the game does alot of pixel work they my want to use fp16 and no AA. it's always a trade off and that depends on what the devs want their games to look like

besides I don't see AA being a problem for most, since most console gamers are used to playing on regular tv's with no AA, the switch to hi def with no AA is not that bad

 

[London Geezer]

I think it still depends on what you want the game to do, I haven't keep up with NAO32 but from what what said before, it lowers pixel shader performance, if the game does alot of pixel work they my want to use fp16 and no AA. it's always a trade off and that depends on what the devs want their games to look like

besides I don't see AA being a problem for most, since most console gamers are used to playing on regular tv's with no AA, the switch to hi def with no AA is not that bad

It's always preferred to have AA as it gets rid of flaws other than jaggies. But that's an old argument i rather not start again.

 

[Shifty Geezer]

NAO32 introduces a pixel shader cost to halve bandwidth requirements. The shader ops needed are for a colour space conversion. I imagine worst-case it'd be <5% of the pixel shader performance available (can nAo add a real figure to this?). For twice the available BW relative to FP16, and with a reported improvement in IQ in most respects, I can't imagine anyone choosing FP16 over NAO32. NAO32 actually works in a logical colourspace. FP16 is just...dumb! Of course I'm sure there'll be situations where FP16 has advantages, but unless NAO32 and variations thereof fail to be communicated appropriately, theoretically I'd expect (and hope) FP16 gets sidelined. Hardware support for HDR should be structured around seperate colour and luminance values because that's what HDR is about; a percentile colour transmission/reflectance to define a surfaces 'colour' and a light intensity. They could add 16 bit FP HDR with only 8 bits more per pixel (40 bit per channel). Stick in some hardware RGB<>HSL conversion too and you're laughing, elliminating those crappy posterized blooms that RGB colour produces.

 

[scooby_dooby]

Oooo, that statement's just asking for trouble! HS features 'a nice amount' of MSAA with HDR. You don't need FP16 for HDR. People have to stop thinking of FP as HDR and vice versa.

Hmm? At first Deano said the game didn't need AA, I think that's probably because it was at 1080p.

Since then he stated they won't be aiming for 1080p anymore, because nobody even has the TV's, I'm assuming that means 720p (he added the clarification the game will 'support' 1080p).

Since then they've also implented NAO32 wwhich is not HDR, and one of the dev made the comment that this frees up bandwidth for a higher degree of AA. Deano originally stated it didn't seem like the game reqally needed AA, but maybe when dropping the resolution, it became a little more necessary.

Soo....HS = 720p w/ NAO32 and 4x or 2x AA methinks!

 

[London Geezer]

Hmm? At first Deano said the game didn't need AA, I think that's probably because it was at 1080p.

Since then he stated they won't be aiming for 1080p anymore, because nobody even has the TV's, I'm assuming that means 720p (he added the clarification the game will 'support' 1080p).

Since then they've also implented NAO32 wwhich is not HDR, and one of the dev made the comment that this frees up bandwidth for a higher degree of AA.

Soo....HS = 720p w/ NAO32 and 4x or 2x AA methinks!

NAO32 is not HDR? News to me...

The whole point of NAO32 is that it lets you use HDR with MSAA at the same time at decent speed, so i'm thinking you might be a bit confused.

 

[scooby_dooby]

I was under the impression it was a workaround to a problem, but by no means a perfect solution. For example, the KZ dev's have stated that method simply wouldn't work for their type of lighting requirements.

 

[Carl B]

I was under the impression it was a workaround to a problem, but by no means a perfect solution. For example, the KZ dev's have stated that method simply wouldn't work for their type of lighting requirements.

I'd be interested in those KZ quotes if you have them; I'm not doubting you in the least mind you.

But as for NAO32 it is definitely an HDR lighting alternative/solution.

 

[London Geezer]

I was under the impression it was a workaround to a problem, but by no means a perfect solution. For example, the KZ dev's have stated that method simply wouldn't work for their type of lighting requirements.

Yes, it's a workaround solution that lets you have HDR and MSAA in a game, rather fast.

Nothing is a perfect solution, all the devs do is create approximations of reality that are more or less adequate. NAO32 is a solution to a problem - the problem being the G70 not being able to do HDR and MSAA at the same time.

That's all.

 

[Carl B]

Yes, it's a workaround solution that lets you have HDR and MSAA in a game, rather fast.

Nothing is a perfect solution, all the devs do is create approximations of reality that are more or less adequate. NAO32 is a solution to a problem - the problem being the G70 not being able to do HDR and MSAA at the same time.

That's all.

Well, it's better than that seemingly. From what I understand, even if you could do HDR and MSAA at the same time on G70, there's few reasons why one would pick FP16 over NAO32 as one stands to gain so much in performance compared to FP16. Plus, the visual differences are aparently quite minor. I remember nAo posting screenshot comparisons, FP16 to NAO32 in fact.

And anyway, I maintain that G71 will allow for FP HDR and MSAA at the same time anyway, and thus probably RSX will as well. So no reason to use this if it wasn't just flat out better for their purposes.

Still I'm interested in knowing what direction the KZ devs are coming from.

 

[mckmas8808]

Well, it's better than that seemingly. From what I understand, even if you could do HDR and MSAA at the same time on G70, there's few reasons why one would pick FP16 over NAO32 as one stands to gain so much in performance compared to FP16. Plus, the visual differences are aparently quite minor. I remember nAo posting screenshot comparisons, FP16 to NAO32 in fact.

And anyway, I maintain that G71 will allow for FP HDR and MSAA at the same time anyway, and thus probably RSX will as well. So no reason to use this if it wasn't just flat out better for their purposes.

Still I'm interested in knowing what direction the KZ devs are coming from.

Scooby is right, the KZ devs did say that the nAo32 HDR was not for them. But like you I'm curious to see what exactly what they use.

 

[London Geezer]

Well, it's better than that seemingly. From what I understand, even if you could do HDR and MSAA at the same time on G70, there's few reasons why one would pick FP16 over NAO32 as one stands to gain so much in performance compared to FP16. Plus, the visual differences are aparently quite minor. I remember nAo posting screenshot comparisons, FP16 to NAO32 in fact.

And anyway, I maintain that G71 will allow for FP HDR and MSAA at the same time anyway, and thus probably RSX will as well. So no reason to use this if it wasn't just flat out better for their purposes.

Still I'm interested in knowing what direction the KZ devs are coming from.

Yeah... i know...

Even then, the word is that NAO32 is much faster than FP HDR, so in the end, even if you can use FP + MSAA in RSX, devs might just want to use NAO32 as it's faster.

Guess we'll have to wait and see. Personally, when i'm there playing the game, i'll hardly give a damn about bloody FP and FX, as long as HDR is there and everything looks good...

Attention span of a red fish...

 

[London Geezer]

Scooby is right, the KZ devs did say that the nAo32 HDR was not for them. But like you I'm curious to see what exactly what they use.

Obviously CGI will need more precise rendering than integer maths.





/runs... very very fast.

 

[mckmas8808]

Obviously CGI will need more precise rendering than integer maths.





/runs... very very fast.

Okay... you know what I meant.

 

[ERP]

there's few reasons why one would pick FP16 over NAO32 as one stands to gain so much in performance compared to FP16. Plus, the visual differences are aparently quite minor. I remember nAo posting screenshot comparisons, FP16 to NAO32 in fact.

If you had a lot of transparency and blending you might want to think twice about NAO32.

 

[blakjedi]

If you had a lot of transparency and blending you might want to think twice about NAO32.

So like games that take place in water or foggy environments?

 

[Carl B]

Attention span of a red fish...

Hey you were the one repeating that the solution to the problem was for HDR and MSAA on the G70 hardware. I was just then repeating my prior statement was all.

 

[Panajev2001a]

If you had a lot of transparency and blending you might want to think twice about NAO32.

Off the gloves, ERPHDR vs NAO32 (hurry, the MSG is almost sold out, fight at 9 P.M. !) .

Just kidding guys, but ERP can you talk a bit more about this hunch of yours ?

nAo was quite confident that this would allow them to use MSAA as WELL as hardware blending and TSAA since the buffers were stored as 32 bits RGBA basically (all calculations were done in the shaders at full FP precision).

I am not clear how you would blend using the hardware (without doing it in the shaders) two off-screen surfaces or an off-screen surface stored in NAO32 with the NAO32 back-buffer: you store in those 4 components, in those 32 bits somethign that is not RGBA data...

I think you would need to blend in the shader, loading up the surface, converting it in FP32, doing the blending and then storing the result.

Other ideas ?