Xbox 360 eDRAM. Where are the results?

[pjbliverpool]

The 360 has 10MB of eDRAM for the frame buffer with a raw bandwidth of 256GB/sec as you all know.

This is well over 10x the framebuffer bandwidth available to PS3 so were exactly is this huge advantage going? This isn't a thread to bitch about one console or the other as both are showing very similar results IMO but therein lies the problem. Given that most of their other GPU resources are fairly comparable, shouldn't we be seeing some amazing things on 360 by now that simply arn't possible on the PS3 due to the massive framebuffer advantage?

Why arn't we? Are there cavaets to the setup that we arn't aware of? Is 256MB simply overkill and not needed for the given processing power?

My understanding is that framebuffer bandwidth is one of the most important and influential elements of a GPU so I just don't get why we arn't seeing the difference between 360 and PS3.

 

[ErnstH]

One of the often mentioned advantages is the lower-cost of MSAA ('near-free'). However, this requires the developer to split the display in multiple tiles, since a 2x MSAA 1024x768 framebuffer does not fit inside this 10 MB. And many developers haven't done so yet.

 

[Shifty Geezer]

Impossible to answer just looking at the games, as the games aren't tied to the GPUs only, but to the entire system. Thus where an XB360 could do lots with alpha-blended particles that RSX would lack the BW for, if the devs create a procedural-particle engine on Cell, the end result could be the same.

The only time you'll see a clear advantage is if the devs did not implement a workaround on the weaker system. And that goes both ways for any aspect of the hardware.

 

[inefficient]

Shouldn't we be seeing some amazing things on 360 by now that simply arn't possible on the PS3 due to the massive framebuffer advantage?

A machine that is a year older than the PS3 but is still managing to hold it's own in the graphics dept qualifies as an "amazing thing" in my book.

 

[22psi]

I think it's a bit too early to tell, most of the engines out there aren't built to take advantage of the edram. Forza 2 seems to be the first game to really start utilizing it however.

 

[scooby_dooby]

I think when 1st party game start moving on from UE3, to proprietary engines is when you'll see much better results. UE3 is sortof a blessing and a curse at the same time

It really was not built for Xenos, yet it dominates the 1st party lineup.

 

[pjbliverpool]

A machine that is a year older than the PS3 but is still managing to hold it's own in the graphics dept qualifies as an "amazing thing" in my book.

Its certainly a testement to the excellent design of the 360 (at least its GPU) but I would argue that we should be seeing even greater results than just parity with the PS3 because of the huge FB advantage.

Shifty raises an interesting argument about using Cell as a work around but I would have thought its ability to make up for much lower FB bandwidth would be quite limited as its generally not a computational limitation but a bandwidth one.

There's also the MSAA advantage that it brings like ErnstH says but im sure a 10x bandwidth advantage must be good for a lot more than that!

 

[Graham]

I think it's a breathing room thing.
If you take away the hit to main memory bandwidth, you bump up the bandwidth avaliable for texturing and other things.
You also get a more predictable framerate. Bandwidth demands is one of those things that is harder to predict.
You get to use a lot more particle effects too. Think of the smoke effects in gears and R6:Vegas, these are using (I'd guess) 5-10 layers of smoke particles, all blended, yet their performance hit is very minimal. This sort of thing eats framebuffer bandwidth.
Games that use stencil shadows are prevalent, at 720p with antialiasing too.. Stencil shadows! At high res! who would have thought it.
Ginormous shadow maps too... They benefit (although not so much)
Splinter cell, etc, with large number of lights on screen (lots of light passes). Hell crackdown has *insane* numbers of on screen lights. All these benefit.
Just look at the effects Graw2 piles on... even in multiplayer... If that isn't 'amazing things' I don't know what is. Let alone other games like lost planet.

 

[inefficient]

Well it's nearly a year and half into the 360's life cycle. And It seems like titles that make good use of the Cell processor will come out in less than a year of the PS3's life cycle.

So either the eDRAM is just is incredibly hard to wield - even in comparison to the Cell processor. Or it is already being put to good use, just not to the extreme effect some might have been expecting.

 

[Jesus2006]

Splinter cell, etc, with large number of lights on screen (lots of light passes). Hell crackdown has *insane* numbers of on screen lights. All these benefit.
Just look at the effects Graw2 piles on... even in multiplayer... If that isn't 'amazing things' I don't know what is. Let alone other games like lost planet.

Aren't all these mutliplaformers (except LP, but the same engine with enhancements is used e.g. for DMC4 in 1080p(?)) with minimal differences (reported up to now)? So that cannot be a big hit for both platforms. I think the advantage of frame buffer bw in the 360 is leveraged by the relatively low main system bandwidth which is shared by all components.

 

[Platon]

Well it's nearly a year and half into the 360's life cycle. And It seems like titles that make good use of the Cell processor will come out in less than a year of the PS3's life cycle.

So either the eDRAM is just is incredibly hard to wield - even in comparison to the Cell processor. Or it is already being put to good use, just not to the extreme effect some might have been expecting.

It could also be that the 360GPU can be used as a "normal" GPU as well, there is no need for them to really take advantage of everything it offers to run games, and very good looking games at that. And still, with most games being based on engines that are made for the generic PC GPU I guess it will take even longer to have games specifically taking advantage of the 360 GPU.

But for the cell what is the alternative, not use it? If you want ot run a game on the PS3 you will have to use the Cell more or less efficiently of course...

 

[Cheezdoodles]

Well it's nearly a year and half into the 360's life cycle. And It seems like titles that make good use of the Cell processor will come out in less than a year of the PS3's life cycle.

What titles make "good" use of the Cell cpu? You pretty much have to use the SPE's for something, because that single PPE wont cut it, not when you look at how CPU bound most games on the X360 are, and that thing has 3 very similar cores.

So either the eDRAM is just is incredibly hard to wield - even in comparison to the Cell processor. Or it is already being put to good use, just not to the extreme effect some might have been expecting.

Its not put to good use yet, Forza 2 , as mentioned earlier will be the first title that really uses the eDRAM for something special, and that is achieving 4x MSAA @ 60fps. Most games out on the X360 are multiplatform, or build on multiplattform engines, they dont support tiling, and the engines are mostly build around traditional PC GPU designs.

It takes time to build a new engine, just like it will take a lot of time before we see the amazing things that the Cell will pull off.

 

[chris1515]

The Xenos has only 8 ROP like RSX. Maybe it is a bottleneck. And I hope more 1st party developer will develop engine tailored to 360 and less UE 3.0.

 

[inefficient]

What titles make "good" use of the Cell cpu?

We have already seen several proof of concept demos that show what the Cell can do when the SPUs are harnessed. Now it's just a matter of seeing them in a shipping retail game.

On the eDRAM side, even on the proof of concept level there hasn't been much in the way of showing us something that really screams the virtues of the 10MB of eDRAM. I think if you polled developers they would agree that case is not closed if it was even a good idea or not.

You pretty much have to use the SPE's for something, because that single PPE wont cut it, not when you look at how CPU bound most games on the X360 are, and that thing has 3 very similar cores.

If the real statistics were known for how many games were using more than one core in a non-trivial way we would all be appalled.

 

[pjbliverpool]

Think of the smoke effects in gears and R6:Vegas, these are using (I'd guess) 5-10 layers of smoke particles, all blended, yet their performance hit is very minimal. This sort of thing eats framebuffer bandwidth.
Games that use stencil shadows are prevalent, at 720p with antialiasing too.. Stencil shadows! At high res! who would have thought it.
Ginormous shadow maps too... They benefit (although not so much)
Splinter cell, etc, with large number of lights on screen (lots of light passes). Hell crackdown has *insane* numbers of on screen lights. All these benefit.
Just look at the effects Graw2 piles on... even in multiplayer... If that isn't 'amazing things' I don't know what is. Let alone other games like lost planet.

Yeah but some of those games are running (or will be running) on PC GPU's with far less FB bandwidth just as well as they are on the 360. So I can't see that they are relying heavily on FB bandwidth for this type of stuff.

 

[Cheezdoodles]

We have already seen several proof of concept demos that show what the Cell can do when the SPUs are harnessed. Now it's just a matter of seeing them in a shipping retail game.

What concept demo's have proven something amazing? Last concept video i saw was of a city @GDC07, which wasnt very impressive, and they used the Cell Blades system(several PS3 Cell's put together)

If the real statistics were known for how many games were using more than one core in a non-trivial way we would all be appalled.

You know this how?

 

[swanlee]

One example is 2XAA+HDR for oblivion on the 360, a year of development later and no AA and only bloom effects for Oblivion on the PS3.

 

[Darkon]

One example is 2XAA+HDR for oblivion on the 360, a year of development later and no AA and only bloom effects for Oblivion on the PS3.

Not this shit again and oblivion on 360 only has 2xAA indoors.

 

[Megadrive1988]

A machine that is a year older than the PS3 but is still managing to hold it's own in the graphics dept qualifies as an "amazing thing" in my book.

the thing is though, Xbox 360 is not really a year older than PS3, even though PS3 came out a year later. The CPUs and GPUs of both systems were completed within less than the space of 1 year. PS3 suffered delay because of Blu-ray component shortage amoung other things.

 

[pjbliverpool]

One example is 2XAA+HDR for oblivion on the 360, a year of development later and no AA and only bloom effects for Oblivion on the PS3.

Thats more a function of the hardware though isn't it? i.e. G7x can't do MSAA and FP 10/16 HDR at the same time (or FP10 at all).

Its not like you need huge framebuffer bandwidth for that task anyway as its easily achievable on a 1900XT with just over 46GB/sec, i.e. about the same as the PS3's total bandwith.