MikeB said: The Cell setup is excellent for throughput. - First step of course is to not share main Ram between GPU and CPU like on the 360, separate buses maximise potential (less latency). - Low latency main RAM, like XDR is crucial for getting the most out of a 8 processor chip like the Cell chip. - But most importantly IMO are the SPE's dedicate memory. They function as real system memory, but operates as fast as cache memory. This together with the huge EIB ring bandwidth is what allows the Cell to reach a near linear performance increases when tapping more SPEs.

 

 The SPEs each have 256K of memory, that's not much. And each SPE can only touch it's own local memory. So memory has to be read from main memory, sent to the SPE, SPE works on it, sent back to main memory.

The Cell is best suited for processing continuous and predictable (no branches) data streams, such as video compression or folding at home. The Cell's useful throughput falls apart for just about everything else because of branching, as the SPEs sit idle most of the time starved for data.

The Cell would be better suited in a Tivo/DVR. I think CELL tests showed it decompressing 12 HD TV streams at the same time.

 

Tyrannical said: ssj12 said: DDR3 @ 2000MHz with three channels is plenty. No, it's not. 22.4GBS memory bandwidth sounds like a lot, but it's not enough to do complex graphical operations like HDR, alpha-blending, and anti-aliasing at 30/60 fps. The 360 does most of that in the 10MB frame buffer, and it has a 256GBS of memory bandwidth between the frame buffer and GPU.

It's not like the Xenos can handle all of that, this due to tiling issues. 10 MB is not enough to fit 720p graphics with Anti-aliasing, that's why demanding 720p games run at 30 FPS instead of 60 FPS. However 640p can fit into EDRAM with anti-aliasing, so a game like Call of Duty 4 can run at 60 FPS.

HDR together with Anti-aliasing is not really an option on the 360 due to tiling issues at HD resolutions. That's why Halo 3 is only 640p and lacking Anti-aliasing, running at an unsteady 30 FPS. Bungie did not lack funds or expertise. But for example Killzone 2's lighting is far more advanced, with more effects, this at 720p with anti-aliasing and a rock solid 30 FPS (they still have a lot of technical headroom though, for a Killzone 3).

Tyrannical said: MikeB said: The Cell setup is excellent for throughput. - First step of course is to not share main Ram between GPU and CPU like on the 360, separate buses maximise potential (less latency). - Low latency main RAM, like XDR is crucial for getting the most out of a 8 processor chip like the Cell chip. - But most importantly IMO are the SPE's dedicate memory. They function as real system memory, but operates as fast as cache memory. This together with the huge EIB ring bandwidth is what allows the Cell to reach a near linear performance increases when tapping more SPEs.    The SPEs each have 256K of memory, that's not much. And each SPE can only touch it's own local memory. So memory has to be read from main memory, sent to the SPE, SPE works on it, sent back to main memory. The Cell is best suited for processing continuous and predictable (no branches) data streams, such as video compression or folding at home. The Cell's useful throughput falls apart for just about everything else because of branching, as the SPEs sit idle most of the time starved for data. The Cell would be better suited in a Tivo/DVR. I think CELL tests showed it decompressing 12 HD TV streams at the same time.

The approach by competent developers of using branch hints and branch elimination results into better performing code than using a predictor can. It will result into better performing code for PC, 360 and other platforms as well. It however requires more effort from developers, implementing this more manually.

The Cell is technically a perfect fit for gaming as well as all kinds of other multi-media uses. With enough effort it's actually powerful at every kind of task, like scientific workloads and procedural synthesis.

256K is both a lot of memory as well as a small amount of memory. Writing 200K of assembly executable code is like writing a bookwork. For executables it's a huge amount of memory to work with. For data processing it's tiny, but the approach with regard to this is entirely different. For this the Cell functions as a stream processor, the data is cut into small pieces and is being processed one piece at a time. The enormous bandwidth is the crucial factor here.

 

 

Well the 360 doesn't have to hold the entire frame in the frame buffer at the same time. It can write it as tiles one at a time, I think it takes 2 tiles at 720p with 4xAA.

Halo 3 did render at 640P, but didn't it render TWO 640p frames and combine them and then stretch them to 720P?

I'll wait for the Eurogame anaysis before I pass judgement on KZ2. I'm curious what their video capture hardware shows.

@ Tyrannical

That's the tiling I was talking about, it directly impacts frame rates.



Eurogamer (UK) is a heavily biased website. They create storms in a glass of water regarding minor porting issues. Overall I share Gametrailers take on things (to my surprise, which I also consider to be overly biased in the past):

Regarding best software line up for 2008:

"And the winner is.... "Playstation 3"!

The tides have truly turned in 2008. Developers finally up to speed with the Playstation hardware, so multi-platfrom games are on equal footing.

Then you have to look at the exclusives for each platform. When stacking up the PS3 holding releases against those of the 360, there's really no contest in quality and quantity"

One major difference between the Xenos and RSX? The Xenos GPU can do 4 AA samples per clock and the RSX can only do two. This goes on top of the bandwidth advantage etc.

@ Squilliam

At lower resolutions having AA does not impact 360 fillrates that much. However there are plenty of high profile 360 games completely lacking anti-aliasing, including (original) exclusives like Halo 3 (best sold 360 game), Kameo (my favourite) and Bioshock (360's Game of the year 2007). That should tell you enough that Anti-aliasing isn't nearly as "free" as Microsoft wants you to believe (this due to tiling).

Either way IMO having full screen anti-aliasing or not does not per se really break a high definition game, there are plenty of design considerations and workarounds to build the best looking console games on the market.

Eurogame actualy uses professional hardware to capture and analyze the frames. So much of what they state in PS3/360 showdowns is facts as they can determine the actual framerate and resolution.

@ Tyrannical

The differences are very minimal. Their focus is selective and mainly judges the porting effort from 360 originals to the PS3. However any gaming expert knows it's the exclusives which normally truly push a system beyond another system's capabilities (you cannot have twice the amount of on screen enemies in one version of the game than another version of the same game, etc, as this would result into an entirely different game).

Some early games had noteworthy issues like Madden 07, but technically when reviewers state Madden 08 is so much better and entirely equal on both platforms. That alone should be an eye opener for less knowledgeable users.

For example with regard to DiRT they failed to focus on audio, to quote the devs:

"Overall Ambisonics complements other aspects of nextGen PS3 game audio, like good quality sample-rate-conversion - rather than the noisy LERPs still sadly common on PCs - plus modern psychoacoustically-modelled decompression, and phase-coherent 512 band filtering on each voice. There’s so much CPU power on PS3 that all this, and multiple reverbs, can run on a single SPU (Synergistic Processing Element, an eighth of the PS3’s Cell processor array) with time to spare.

There are six independent reverb units running in the PS3 version, versus two stereo ones on Xbox360."

Yet they make a big deal of GTA IV's movies running at 24 FPS per second (just like Hollywood movies) vs slightly higher on the 360. Those movies aren't exactly fast paced and look smooth in terms of animation on the PS3 (overall most agree the game actually looks better on the PS3).

Addressing all the games would require writing a bookwork, but really overall they are creating storms in a glass of water. Port quality is now more than acceptable on the PS3, sometimes the 360 has a very slight edge and sometimes the PS3 like with Tomb Raider Underworld rendering in a better resolution, but in any case it's still a far cry from Uncharted: Drake's Fortune technically. Such games are the ones to judge a platform on.

Who cares if in 2009 about a relatively low profile game running marginally better on the 360 (Yes, I know the answer, 360 fanboys of course), when we will have exclusive games like God of War 3, Killzone 2 and Heavy Rain to judge?

To me is still a mistery why RSX does not have any embedded memory.