The Game Technology discussion thread *Read first post before posting*

[brain_stew]

It depends on what theyre doing
GPUs are fast dumb machines
CPUs are slower intelligent machines

cell is somewhere in the middle

yes for certain grafix things cell can run rings around what a GPU (though the latest + future GPUs from ATI/nvidia are catching up)

6msec though is a long time, think of it as 60fps == 16.7 msec per frame ( thus youre approaching half your available time!)
30fps == 33.3msec

Yeah, but that 6ms is when using just two SPUs and the PS3 has seven (or six depending on how the OS reserves resources) at its disposal. Are we suggesting that developers are using all the resources that the SPUs have to offer in their current engines?

With most games targetting 30fps, is using less than 1/5th of the resources of just two of those SPUs to add a very impressive and beneficial effect really that expensive? I'd argue the opposite, its probably resources that a lot of engines could give up without any impact on performance, but give a huge benefit to many scenes. Wasn't Killzone 2 only fully using 4 SPUs according to that presentation they released? Surely we'd expect third paty titles to be making less effective use of the SPUs, no?

I dunno, I'm well aware those figure are just guidelines but that sort of performance sounds very encouraging to me.

Edit: Just een the mod note above, apologies, feel free to move this post elsewhere.

 

[liolio]

Yeah, but that 6ms is when using just two SPUs and the PS3 has seven (or six depending on how the OS reserves resources) at its disposal.

Actually you're right and wrong
there are seven usable spu in the cell, one is taken for the OS hypervisor, another one can be used by OS/hypervisor from time to time. Devs have 5 (sure) and something to play with.

Are we suggesting that developers are using all the resources that the SPUs have to offer in their current engines?

Well ND stated so even in some PR stunt. Could be true and that would not mean that they can't do better with those resources anyway

 

[brain_stew]

Actually you're right and wrong
there are seven usable spu in the cell, one is taken for the OS hypervisor, another one can be used by OS/hypervisor from time to time. Devs have 5 (sure) and something to play with.

Well ND stated so even in some PR stunt. Could be true and that would not mean that they can't do better with those resources anyway

Oh, I'm sure Naughty Dog are (and SSAO is probably one of the good uses they have for them, heh) but I was talking more in regards to your average third party developer here, who one would expect not to be on quite the same level as Naughty Dog or Guerilla games when it comes to making good use of the SPUs. What are the restrictions on that 6th core then? Would reserving 6ms in a 30fps title (i.e. around ~20% of resources) for SSAO be too much? If so, then yeah that changes things and it definitely makes that performance figure become less attractive. Now, if only developers had full access to the proper 8 SPU chip.............

 

[marcus_rocks]

One question for Joker454:
With the advantage of high bandwidth, why is Forza 3 limited with transparencies (cannot see through car glass window) whereas GT5P has abundance of transparencies and sports a 4xMSAA?
I think we cannot point our finger at one single factor and declare the winner. There are many ways to work around the problem.

 

[Neb]

I thought you could see through Forza 3 windows it is just that they are very dark to hide "lack of detail inside" (as in missing drivers or such?). And then it has pretty much rock solid 60fps. Also is tiremarks and smoke a factor here?

 

[Crossbar]

One question for Joker454:
With the advantage of high bandwidth, why is Forza 3 limited with transparencies (cannot see through car glass window) whereas GT5P has abundance of transparencies and sports a 4xMSAA?
I think we cannot point our finger at one single factor and declare the winner. There are many ways to work around the problem.

This is something I would like know as well. How can GT5P on the PS3 pull off 720p with 4xMSAA at 60 fps without EDRAM, still FM2 on the 360 (with EDRAM and "free" MSAA) is limited to 2XMSAA?

Has PD discovered some clever way of working around the limited memory bandwidth of the PS3, that other developers have yet to discover and/or is the tiling required for 4XMSAA on the 360 to "expensive" for 60 fps?

Any theories about this?

 

[Rotmm]

(cannot see through car glass window)

Huh?

Any theories about this?

Rolling starts means fewer cars to render on-screen maybe?

 

[Crossbar]

Rolling starts means fewer cars to render on-screen maybe?

Given that GT5P allows up to 16 cars races, I don´t think it´s that difficult to get 8 cars on screen at the same time. If I remember correctly GT5P has races that start from stand still as well, but I am not sure that was 16 cars races. Anyone?

 

[marcus_rocks]

Huh?

it uses lower resolution buffer for the transparent objects and it uses dark colors to hide the details of the car's interior.

 

[Arwin]

Given that GT5P allows up to 16 cars races, I don´t think it´s that difficult to get 8 cars on screen at the same time. If I remember correctly GT5P has races that start from stand still as well, but I am not sure that was 16 cars races. Anyone?

Online races on Suzuka and Fuji start from stand-still and this includes 16 car races.

 

[Rotmm]

it uses lower resolution buffer for the transparent objects and it uses dark colors to hide the details of the car's interior.

Huh?

http://www.gamersyde.com/stream_forza_motorsport_3_nrburing_lap_part_1-13275_en.html

 

[Crossbar]

Online races on Suzuka and Fuji start from stand-still and this includes 16 car races.

Thanks, there you go. GT5P even allows more cars on the screen at the same time. Other theories?

 

[Arwin]

Thanks, there you go. GT5P even allows more cars on the screen at the same time. Other theories?

They made a certain choice for Forza 2 that isn't optimal, but didn't radically overhaul their graphics engine? That's my theory anyway. Forza 3 looks better than Forza 2, but it's not a fundamental difference that suggests a complete rendering pipeline rewrite, imho.

 

[Neb]

About Forza 3, how does tiremarks, smoke, vegetation amount and detail factor up regarding transparencies?

 

[marcus_rocks]

Huh?

http://www.gamersyde.com/stream_forza_motorsport_3_nrburing_lap_part_1-13275_en.html

This is what I was referring to.

 

[Rangers]

This is something I would like know as well. How can GT5P on the PS3 pull off 720p with 4xMSAA at 60 fps without EDRAM

It isn't exactly a hard 60 FPS is it? I mean according to the frame counter videos I've seen it dips when other traffic arrives.

Edit: http://www.youtube.com/watch?v=kVtJDhsfwn0

 

[Neb]

Gamersyde had some borked screenshot of Forza 3 which was admitted by Gamersyde staff (problem with capture tool). The images looked like above, pixelated. IIRC there was talk about that in this forum.

 

[nightshade]

IIRC they use A2C for foliage...& its strange considering its a 360 game made for that platform..Smoke/Dust in FM3 is very very less compared to GT5P (But donno if its a lower reso buffer or full )

 

[Crossbar]

They made a certain choice for Forza 2 that isn't optimal, but didn't radically overhaul their graphics engine? That's my theory anyway. Forza 3 looks better than Forza 2, but it's not a fundamental difference that suggests a complete rendering pipeline rewrite, imho.

I guess their design choices will remain secret to us, but it still bugs me. We are repeatedly told that the 360 is a MSAA juggernaut due to the EDRAM, while the PS3 is not. These games are exclusives and should cater to each platforms strength, yet FM3 seems to hold back in this department. Maybe its just a business decision to keep 4XMSAA as a feature that will be included in FM4, to make the visuals more different at the time of its release?
Nevertheless, what trick is PD pulling off to get 4XMSAA in a 60 fps game as 4XMSAA is rarely seen in any 30fps PS3 game?

It´s all very weird. Yeah, it really bugs me.

 

[Neb]

But didn't EDRAM and higher AA increase polygoncount as in multipass?

Do I remember it right with 2xAA -> 15% polygon redraw and 4xAA 30%?