360-to-PS3 Ports: Why the Lowered Texture Resolution?

[bigsilly]

Hi!

I've noticed in most of these PS3 versus 360 screenshot comparisons that the textures in the PS3 ports seem to have been lowered in resolution. What is the technical reason for this? Is it because PS3's computing is better for non-graphics tasks, or is it simply because the programmers who make the ports do not know how to utilize the PS3's architecture?

 

[AlNom]

A couple things:

1) The backbuffer isn't stored in main memory on the 360.
2) The OS footprint on 360 has always been much smaller than on PS3.


There was a big discussion about it awhile back. I'd suggest searching console tech thread titles for "memory". Here's one example: http://forum.beyond3d.com/showthread.php?t=28419

You may also want to check Dave Baumann's posts on eDRAM.

 

[grandmaster]

I think the problem is far less of an issue than it used to be - certainly we don't see ports as shockingly awful as Splinter Cell: Double Agent any more. Indeed, in some cases we see better effects and higher quality textures on some PS3 titles - the road textures are slightly better on PS3 Burnout Paradise and the grass/ground textures in Turok are similarly better-looking on PS3.

In terms of what the issue could be, I think I'm right in saying that PS3's texture memory is hard-set to 256MB whereas on Xbox 360, developers can take as much of the onboard 512MB RAM as they want. Similarly, I'm also fairly sure that the OS footprint of Xbox 360 is still a fair bit lower than it is on PS3.

 

[Shifty Geezer]

There is no hard-limit exactly, although you do have to 'reach further' to use the XDR for texturing. Some devs may be using the GDDR as a VRAM cap though.

 

[Laa-Yosh]

Indeed, in some cases we see better effects and higher quality textures on some PS3 titles - the road textures are slightly better on PS3 Burnout Paradise and the grass/ground textures in Turok are similarly better-looking on PS3.

It's not the textures, it's the better anisotropic filtering performance of the RSX. Which is also the reason why the difference is more prominent on walls and floors.

 

[Quaz51]

It's not the textures, it's the better anisotropic filtering performance of the RSX. Which is also the reason why the difference is more prominent on walls and floors.

no for Turok really better ground resolution texture on PS3

but maybe because X360 use another layer of map for different lighting or normal mapping? i don't know, i don't remember

 

[Quaz51]

A couple things:

1) The backbuffer isn't stored in main memory on the 360.

if you use tiling the backbuffer is stored in main memory too and majority of X360 game use tiling

 

[AlNom]

if you use tiling the backbuffer is stored in main memory too and majority of X360 game use tiling

Ah, the tiles are compressed when the eDRAM is finished with each tile, at least that's what Wavey has said in the past.

When the frame or tile has finished rendering, the colour data will then be resolved on the daughter die, with the Multi-Samples being blended down to their pixel level. The resolved buffer information is then passed back from the daughter die to the parent which then outputs to system RAM such that, when all the tiles are finished, this can then be outputted to the display device.

Maybe it's an extra detail that wasn't mentioned, but why would you need to store the entire back buffer into system memory with tiling?

 

[assen]

The tiles aren't "compressed" but "MSAA resolved", meaning the subsamples are merged into pixels.

The backbuffer must go into system memory because that's where the RAMDAC needs it to get it to the screen.

Another theoretical reason for lower texture resolutions in games with heavy streaming is the lower throughput of the Blu-ray disc; if the Xbox360 version dedicates the outer portion of the DVD for streaming textures, and keeps less-bandwidth intensive and time-critical things like music and voiceovers on the inner part, the PS3 version will have to do with about half the bandwidth for these textures, or resort to installation. I doubt this has been ever the case in practice, though.

 

[AlNom]

The tiles aren't "compressed" but "MSAA resolved", meaning the subsamples are merged into pixels.

Sorry, that's what I meant. "Compressed" from the higher sampling of MSAA to the pixels.

The backbuffer must go into system memory because that's where the RAMDAC needs it to get it to the screen.

Doesn't the RAMDAC use the frontbuffer to display the image Well, I suppose my question is, why does the RAMDAC need access to the multisampled/subpixel information ?

http://forum.beyond3d.com/showpost.php?p=1104347&postcount=5

Back-Buffer(s) = Pixels * FSAA Depth * Rendering Colour Depth
Z-Buffer = Pixels * FSAA Depth * Z Depth
Front-Buffer(s) = Pixels * Output Colour Depth
Total = Back-Buffer(s) + Z-Buffer + Front-Buffer(s)

 

[TimothyFarrar]

Why the Lowered Texture Resolution? Bad ports! Developers using PSGL instead of GCM.

 

[Mintmaster]

Indeed, in some cases we see better effects and higher quality textures on some PS3 titles - the road textures are slightly better on PS3 Burnout Paradise and the grass/ground textures in Turok are similarly better-looking on PS3.

In Burnout it seemed several people came to the opposite conclusion. Here's an example:
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_360.png
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_PS3.png

I think the PS3 version of Burnout Paradise was deemed better due to the fewer framerate hitches as opposed to better image quality.

 

[vazel]

Isn't also because some PS3 titles use Quincunx AA which blurs the image.

 

[Nesh]

In Burnout it seemed several people came to the opposite conclusion. Here's an example:
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_360.png
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_PS3.png

I think the PS3 version of Burnout Paradise was deemed better due to the fewer framerate hitches as opposed to better image quality.

Burnout comparisons are pretty inconsistent. In other images the PS3 may show better detail in some sections. In others it is the 360. I dont think it looks better in any of the 2 consoles.

 

[zarbaj]

In Burnout it seemed several people came to the opposite conclusion. Here's an example:
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_360.png
http://yoda.dip.jp/Game/BurnoutP/BurnOutP_11_PS3.png

I think the PS3 version of Burnout Paradise was deemed better due to the fewer framerate hitches as opposed to better image quality.

they fixed the 360 framerate via a patch later.

 

[TimothyFarrar]

All these PS3 vs 360 comparisons are mostly ridiculous. If there is a crappy port, if they lead on 360 the PS3 port will typically be crapper, if they lead on PS3 the 360 port will typically be crapper. You engineer for the advantage of one platform, you loose optimizations which can be done on the other. If you take the lowest common denominator you loose on both platforms to an extent. IMO it has everything to do with decisions which have nothing to do with the capacity of the hardware and everything to do with legacy code, development tools, management choices as to what to engineer for, etc.

As for texturing, there is no reason that you cannot get high quality textures on both platforms if you have a good texture streamer. If anything PS3 has an advantage here in the possibility of more unique texturing per game because of blue ray capacity and the ability to always cache on the HDD.

 

[ShaidarHaran]

All these PS3 vs 360 comparisons are mostly ridiculous. If you lead on 360 your PS3 port will typically be crap, if you lead on PS3 your 360 port will typically be crap. You engineer for the advantage of one platform, you loose optimizations which can be done on the other. If you take the lowest common denominator you loose on both platforms to an extent.

As for texturing, there is no reason that you cannot get high quality textures on both platforms if you have a good texture streamer. If anything PS3 has an advantage here in the possibility of more unique texturing per game because of blue ray and the ability to always cache on the HDD.

Are you saying that others claiming that developing for PS3 and porting to 360 allows the most benefits of each platform to be retained (thanks to the best-practices of Cell programming) are wrong? Seems a rather logical statement to me. If you have practical experience demonstrating otherwise though, I'd love to hear it. I personally have none, so I'm merely asking questions at this point.

 

[chachi]

Are you saying that others claiming that developing for PS3 and porting to 360 allows the most benefits of each platform to be retained (thanks to the best-practices of Cell programming) are wrong? Seems a rather logical statement to me.

I'll say it: they're wrong, or disingenuous. What system you start or lead development on has nothing to do with the quality of the port. The idea that developers will ignore programming practices that are good on the 360 as well as the PS3 just because they lead on the 360 doesn't make sense unless that developer just doesn't have much experience, in which case leading on a system they can't figure out in the first place probably isn't a good thing.

What they're really saying, if you read between the lines, is if you lead on the PS3 and port to the 360 then you (probably) won't see a disparity between the two versions that cause PS3 owners to get bent out of shape and start ranting about lazy developers.

Oh well... sore point. I think it's better to have a high bar set and try to match that rather than aim for the lowest common denominator. I'd also like to see developers play to the strength of the particular consoles (e.g. PS3 is supposed to be much more capable at physics, etc.) but business realities apparently prevent this.

 

[Jesus2006]

Oh well... sore point. I think it's better to have a high bar set and try to match that rather than aim for the lowest common denominator. I'd also like to see developers play to the strength of the particular consoles (e.g. PS3 is supposed to be much more capable at physics, etc.) but business realities apparently prevent this.

Are you saying that porting from 360 to PS3 is like setting a high bar (for PS3)?
I'd believe that if there weren't other (also mulliplatform) games on PS3 that prove that this high bar is very often far below from what is possible on PS3 and in the end it's up the those developers again.

 

[assen]

If anything PS3 has an advantage here in the possibility of more unique texturing per game because of blue ray capacity and the ability to always cache on the HDD.

I don't believe anyone would budget the production of more textures just for the PS3 version of the game. Not today, not in 2009. Maybe after that, if everything goes the best possible way for Sony and the worst possible way for Microsoft.