Forums - Sony Discussion - IBM continues Cell development

Kynes said:

Please explain how cell is good doing AA resolve, with technical reasons, not with void words.

Flexibility, there are different methods and approaches for doing AA (and the need for this also depends on rendering resolution, art direction and other lighting/color effects as well).

I better link to another discussion, so you won't be upset with me.

http://forum.beyond3d.com/showthread.php?p=1360606



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales

Around the Network

Do you know what I confirm thanks to that thread? That you don't understand what they are talking there. Please read it again and tell me where they say a SPU is better than dedicated hardware doing AA resolve.

Flexibility doesn't equals to high performance. One of the limitations of RSX is that nVidia (unlike ATI since DX9 cards) had fixed AA resolve patterns in it's chips, so you can't create new AA methods/patterns. Doing AA resolve in a SPU is slower than doing it in the dedicated hardware of RSX. The only advantage is that you can chose better patterns, higher number of samples... in non performance critical situations. But AA in SPU is much slower.



@ kynes

Halo3 to compare AA methods is a crappy way


Feel free to use any other 360 game as an example instead. It doens't make much of a difference, games like Killzone 2 and Uncharted 2 sport more impressive lighting than any 360 exclusive, are rendering in 720p and include good anti-aliasing.

With regard your bolded highlighted question, I don't understand you as wasn't that the first comment you asked this question anyhow. If I ignored it, I would better understand your behaviour.



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales

MikeB said:
@ kynes

Halo3 to compare AA methods is a crappy way


Feel free to use any other 360 as an example instead. It doens't make much of a difference, games like Killzone 2 and Uncharted 2 sport more impressive lighting than any 360 exclusive, are rendering in 720p and include good anti-aliasing.

With regard your bolded highlighted question, I don't understand you as wasn't that the first comment you asked this question anyhow. If I ignored it, I would better understand your behaviour.

I bolded that question because you ignore things when people point to a cul-de-sac in your propaganda. Regarding examples, I'm not the one who has to find a counter-argument. You said that Cell is great doing AA, you're the one that has to explain the reasons, and flexibility is not a valid reason in this question because such flexibility means very low performance.



Kynes said:

Do you know what I confirm thanks to that thread? That you don't understand what they are talking there. Please read it again and tell me where they say a SPU is better than dedicated hardware doing AA resolve.

Flexibility doesn't equals to high performance. One of the limitations of RSX is that nVidia (unlike ATI since DX9 cards) had fixed AA resolve patterns in it's chips, so you can't create new AA methods/patterns. Doing AA resolve in a SPU is slower than doing it in the dedicated hardware of RSX. The only advantage is that you can chose better patterns, higher number of samples... in non performance critical situations. But AA in SPU is much slower.

Where did I say it is faster per se than having the RSX do anti-aliasing using a different method, the best method to use depends upon the specific game in question anyhow.

I am just saying doing anti-aliasing on the XBox 360 is costly performance-wise rendering in 720p or beyond due to tiling issues. That's why many 360 games don't do full anti-aliasing including top exclusives (despite Microsoft in the past claiming the 360 can do anti-aliasing for "free").



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales

Around the Network

@ Kynes

You said that Cell is great doing AA


Compared to what?

- I said it can do AA and flexibility is a benefit.
- I said the 360 does not have a real technical advantage regarding anti-aliasing.

I didn't say anything with regard to performance vs the RSX, however I can imagine this flexibility to provide for potentially big benefits and this approach to be used efficiently together with other deferred rendering techniques.



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales

MikeB said:
Kynes said:

Do you know what I confirm thanks to that thread? That you don't understand what they are talking there. Please read it again and tell me where they say a SPU is better than dedicated hardware doing AA resolve.

Flexibility doesn't equals to high performance. One of the limitations of RSX is that nVidia (unlike ATI since DX9 cards) had fixed AA resolve patterns in it's chips, so you can't create new AA methods/patterns. Doing AA resolve in a SPU is slower than doing it in the dedicated hardware of RSX. The only advantage is that you can chose better patterns, higher number of samples... in non performance critical situations. But AA in SPU is much slower.

Where did I say it is faster per se than having the RSX do anti-aliasing using a different method, the best method to use depends upon the specific game in question anyhow.

I am just saying doing anti-aliasing on the XBox 360 is costly performance-wise rendering in 720p or beyond due to tiling issues. That's why many 360 games don't do full anti-aliasing including top exclusives (despite Microsoft in the past claiming the 360 can do anti-aliasing for "free").

 

You said "To Clarify, the Cell's SPUs can act as very powerful and flexible stream processors. This due to very high internal bandwidth and very high speed dedicated memory available to each SPU.

For example when anti-aliasing is done on the SPU or when processing 7.1 surround audio, small chunks of data is processed at very high speed, just a small part at a time."


That's false, at least regarding AA resolve. You could use Cell to do AA resolve if you're using SPUs to do some other full screen shader filter, as SSAO, you already have the buffer in XDR RAM, as AA resolve, in this scenario, is several times faster than this type of filtering (when you are forced to stream the graphics data to the SPU, doing AA resolve is cheap) The problem is that you won't find this scenario in almost any game, because doing these full screen shader filtering is very costly in a SPU, due to bandwidth limitations.


It seems that you like to quote Beyond3D threads. You can take a look at the resolution and AA method in games thread, you'll find that there are much more games using 720p and AA in X360 than in PS3, exclusives or not, and a lot of PS3 games use quincunx AA, that blurs the entire image with a notable loss in quality:

http://forum.beyond3d.com/showthread.php?t=46241



@ Kynes

It was an example of stream processing.

The quincunx anti-aliasing method works better with some games than others. Usually I would prefer just edge blurring like used in top animation movies.

As to why "The Saboteur" developers are doing FSAA on the Cell and no AA at all on the Xenos in the XBox 360 version you will have to ask the developers for specifics. Probably it is performance related (tiling issues). Usually multi-platform titles are designed around the 360's strenghts and weaknesses (and thus sometimes difficult to port or make good use of the PS3 hardware), this may be one of those exceptions.



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales

MikeB said:
@ Kynes

You said that Cell is great doing AA


Compared to what?

- I said it can do AA and flexibility is a benefit.
- I said the 360 does not have a real technical advantage regarding anti-aliasing.

I didn't say anything with regard to performance vs the RSX, however I can imagine this flexibility to provide for potentially big benefits and this approach to be used efficiently together with other deferred rendering techniques.

 

Any programable processor is more flexible than fixed function, but it doesn't means that is practical (ATI R520 is an example of a debacle due to not using fixed function to do AA resolve)

Regarding to 360-PS3 AA: http://forum.beyond3d.com/showthread.php?t=46241

RSX - The relation to the G7x series would mean that the ROPs are capable of handling 2 multisamples per pixel per cycle. Basically, in a bandwidth unlimited scenario, 2xMSAA or Quincunx is free. But do note that the double pumped Z-only fill rate is only effective without MSAA and that this can be important for certain effects such as rendering shadows; with 2xMSAA the z-only fill rate falls in line with the colour fill rate.

However, with the use of multiple render targets or higher resolutions, the 22GB/s is very much a concern for framebuffer bandwidth. 4xMSAA would be very costly to fillrates, halving the rates compared to 2xMSAA and also doubling memory bandwidth consumption since the framebuffers scale linearly.

Xenos -
As noted in the B3D article, the ROPs are designed to handle 4 multisamples per pixel per cycle. All fill rates are full speed, and the Z-only fill rate is also double pumped.

RSX is a fillrate/bandwidth starved chip. That's the reason why in some cases PS3 games have a blur filter instead of AA, because a blur filter is more compute intensive than bandwidth intensive. You can't help it's bandwidth problems doing AA resolve on a SPU.



@ Kynes

RSX is a fillrate/bandwidth starved chip


Someone forgot to mention this to Naughty Dog.



Naughty Dog: "At Naughty Dog, we're pretty sure we should be able to see leaps between games on the PS3 that are even bigger than they were on the PS2."

PS3 vs 360 sales