Nonetheless there is biases and platform of choice (F@#boies exist for developers as well)! I'd be more interested to hear an in depth developer nuetral assesment of both platforms (seems to be a very diffucult task at hand).
RSX: Vertex input limited? *FKATCT
- Thread starter Hypx
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Nonetheless there is biases and platform of choice (F@#boies exist for developers as well)! I'd be more interested to hear an in depth developer nuetral assesment of both platforms (seems to be a very diffucult task at hand).
ShootMyMonkey
Veteran
Well, that's probably true if you're vertex-limited in some way, whether it be attributes or shader instructions or something similar. Well, I don't know anything about your game(s) or what you're working on to say anything for sure, but that is definitely not a boat you want to be in regardless of your platform. Since I'm having to worry not only about Xenon and PS3, but also PC, it's generally the case that all our assets are going to be somewhat sparing on the vertex count. Plus, we have artists who understand the concept of constructing geometry that has very low vertex:tri ratios. As long as we can keep things sitting in the post-transform cache as long as possible, GPUs smile at us.
Unless "we" means "we, in particular"...
More than anything else, Gears was a victory of artwork. Technology-wise, it's not doing anything super-special even if their way about it might be unique. The thing is that to say it was mainly about artists and design and stylistic consistency suggests to the average person that any team could have done it (which in fact is true), but the fact that there isn't another Gears of War out there right now tells them "it's all about something unique to UE3."
Really? I can't say nAo's sentiments on that are all too unique. Usually, when I say something to that effect though, I mean it in a negative light -- i.e. they both suck equally bad. For all you could say about RSX's vertex throughput limitations, I can't tell you that Xenos is out of this world. Just easier to run with out-of-the-box.
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thanks for your perspective.
I don't understand why some appear upset that Joker has said that RSX is vertex limited. Did they not expect some trade offs compared to Xenos?
People have been mentioning here for a year that cell would be helping RSX. Only now when we can compare systems based on designing for multiplat games do we find that it needs to help RSX to equal Xenos in some areas. That reduces some of what Cell can do in other areas, but MS made similar trade offs when they invested heavily in making Xenos powerful (easier?) but do not have a beast like Cell in their system.
exactly.... trade offs.
I think we agree to disagree on this.
Well..yes and no.. given the amount of stuff they have on screen I'm not really impressed...but I can see how very big normal maps can impress a lot of ppl
C'mon, you know there's way more to it than that.
Both boxes have limited fillrate. Games that have alot of overdraw will falter at 1080p because both machines can only draw so much. This may not affect driving games very much where the only transparencies are some dirt being kicked up, but in games with lots of explosions you will take a framerate hit at 1080p. This is very easy to test on PS3. When you build your test disk, just select 1080p and compare it to your framerate at 720p. On our game the framerate is staggeringly different, it's unplayable at 1080p. Incidentally this brings out one of the plusses of the rsx, targeting 1080p or 720p is trivial, its just a checkbox away. You have to tile on 360 to use 1080p which blows.
How can you match it on PS3 when you have less available memory to work with? You can argue vertex tricks here, packing tricks there. But when it comes to memory, the only choice is to start half sizing textures. Further, the 360 is more flexible when it comes to texture formats. For example, we can use compressed normal maps on 360 to save even more memory, we can't do this on PS3. Much of our time was spent just getting the game to fit in PS3's available memory. You can use DXT1 or DXT5, but only DXT1 stays compressed in the PS3's texture cache so using DXT5 incurs a performance hit. Further yet, on 360 because its shader units are unified, we can allocate more to pixel processing or vertex processing if we're more performance heavy on one or the other. No such option on PS3 because its shader units are fixed. I'm sure you can argue that there exists trick x, y and z to get around some of these issues. But on 360, we can use tricks *and* leverage the natural advantage that its gpu gives us.
This may be true. I have yet to meet one though, maybe I've just been unlucky
?! PS3 is already matching 360 now, with (probably) inferior tools and less experience on the system wrt 360, it can only get vastly better, no doubt about it. Non multiplatform titles are going to show this quite soon imho
I fully agree....the dev tools on 360 are miles ahead of the tools on PS3. I definitely disagree that PS3 is matching 360 now. I honestly don't see this at all, and judging from side to side comparisons, neither do others. Am I wrong on this? I'll let others chime in with their opinions. 360 will get much better as well. You'd be surprised how few games are actually using all 6 hardware threads on 360.
I'm going to add to this... that let's let others chime in with their educated opinions. There's already some tension starting to enter the thread; let's all try to keep it civil and on-topic.
(Joker though I'm quoting you to post that, understand that it wasn't directed at you.)
ShootMyMonkey
Veteran
Mmmm... you've got two pools of memory from which to texture if you really need the space -- and you get extra texture bandwidth out of it to boot. On top of that, there are a million and one ways to get much higher *effective* resolution than Gears of War exhibits while still using less texture memory and less *physical* texture resolution. Our artists have gotten really smart when it comes to these kinds of games, and they do a decent job of it on characters, but an even better job in general on environments.
I think the nature of the fact that modern graphics demands the creation of textures that aren't just about appearances but also about parameters for larger computations means that artists need to be more technically inclined than they used to be a few years ago. When they are, it turns out to be a very good thing.
While the 360 is definitely more flexible in its texture formats, I don't see how DXN saves "even more" memory. Who says you can't drop components and just use DXT#? It does work pretty well, FWIW.
Again, pointing more to the same vertex throughput issues. If you're pixel-shader limited on RSX, you'll very likely be even more so on Xenos. And yeah, I know you don't like the idea of having to do something differently because of a specific platform's specific strengths and weaknesses, but at the same time, you're working at a multi-platform developer. There will never be a day in your life where you won't suffer this kind of trouble. It doesn't matter if it's this generation or 4 console generations from now, assuming you're still at a multi-platform dev house through all that time.
Actually, I'd be more surprised if you could name that many games that DO consistently use all 6 hardware threads. All the same that I'd be surprised if you could name all too many games that consistently use all the SPEs (likewise to XeCPU's threads, I mean using in a non-superficial way) you've got on PS3. It's safe to say that we're hardly anywhere with any of the platforms (including Wii). I just hate the smorgasbords of stupidity that come about when companies put out press that "we're only using 20% of the PS3's power" and the obsequious dunderheads on forums everywhere scream that the graphics will be 5x better by the time PS4 comes out...
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I would hope Sony provides all developers with the same information and tools. If they don't they are doing a disservice to themselves.
I expect games to always use automatic load balancing, but they will nudge the chip in one direction. I'm not sure if Microsoft has exposed a way to forego automatic load balancing completely.
Can you give any details on why this might be the case? Tests? Or are you considering the "24" pixel ALUs of RSX to be superior to the 48 ALUs (minus a few for VS work) in Xenos?
I would like ask if any the devs have seen instances in a game that the Xenos has used all of it's SIMD units for pixel work at any given clock? Same question for vertex work.
24 fragment processors - 2 ALUs per fragment processor. (ignoring mini and fog alu)
dedicated to fragment processing and texturing.
TurnDragoZeroV2G
Regular
Perhaps more the pitfall of having a 1:3 TMU:ALU ratio at present?
But the TMUs are decoupled completely so as to reduce dependencies in the pixel shader no? If there is so much texture sampling/lookups that the TMUs can't keep pace then you're texture bound. Maybe I'm off but what I gather is that ShootMyMonkey was speaking to being limited on fragment throughput more so than texturing operations.
If I misunderstand ShootMyMonkey is of course free to correct me.
TurnDragoZeroV2G
Regular
What do you consider to be the basis of fragment throughput, then?
Edit: To not just sit here adding noise to the thread (or attempt avoiding it, at least):
Can one really separate texture sampling, or any of the other fixed function/programmable sections of the "pipeline" from fragment processing? Texturing is one of the primary means of reading data into the fragment processing pipeline, the ALUs being the primary means of manipulating those data.
I can't presume to know specifically to what SMM was referring, hence my (needless) blurb of a comment. However, it's not a simple case of "oh, you're texture limited"--to then be passed off so easily. We've seen the heavy math:tex ratio of Fran's postprocessing shader as compared to what may be more standard on PS3 or a PC GPU. Amongst the numerous performance presentations by MS are notes regarding how you handle texture fetches (i.e, when and where they're called for, balancing out with register usage), packing in more math, etc. There were several events, and Jawed had a few posts IIRC. It's probably not an ideal scenario, and one probably has to either cater to one and suffer performance penalties on the other (both ways! Texture fetch-related penalties on Xenos and a wasting of texture fetches on RSX), sit your shader somewhere in the middle and not extract everything from either one, or tailor the shaders to each GPU.
But, as you said, if the developers haven't already become completely sick of this thread, they'll (hopefully) correct any/everything there.
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This is a more accurate way to word it. We get very limited control, but we can nudge it either way. The PIX gpu tool lets you know which way to nudge it, and even gives you a % estimate of speed improvement. In our case we did nudge it and did see an improvement, but I won't get into specifics. PIX is quite a marvelous tool indeed. A similar tool is being written for PS3 but we don't have our hands on it yet.
I could easily construct tons of cases where exactly the opposite is true (rsx would run way faster than xenos) and I would have still proved nothing.
Sometime tricks benefit both platforms, sometimes they help a platform and harm the other one.
to say "everything we do to make RSX run faster help Xenos as well (or the other way around)" is imo naive at best.. Even in this case I could make a couple of examples related to vertex streams attributes..unfortunately NDAs don't allow me to do that.
Well..yes and no.. given the amount of stuff they have on screen I'm not really impressed...but I can see how very big normal maps can impress a lot of ppl
I really cant find any logic in this argument. Why do you think that GOW would be bw limited at 1080p more than it's at 720p?
Yes, GOW is prettier..so what?
Maybe you should check the internal ps3 devs forum more often than, you're not the only one that have worked on both platforms and you might be able to find ppl that agree with you and ppl that don't agree with you at all and that have the opposite experience.
I'm not really suprised by that cause every team has different engines..with different requirements..something that runs good on RSX can run not so good on 360.
Generalizing is not particularly smart..
And I'm even talking about old school programmers that hate Microsoft with a passion! Even they, privately, give the nod to 360 in graphics. Although they will usually immediately follow it up with a lengthy discussion of the joys of cell
?! PS3 is already matching 360 now, with (probably) inferior tools and less experience on the system wrt 360, it can only get vastly better, no doubt about it. Non multiplatform titles are going to show this quite soon imho
No offense nAo, but don't you seem to be a tad too enthusiastic about the PS3? I know you have more experience developing with the system, but comparing what joker and other devs have been saying, your posts read as if PS3 has no weaknesses compared to Xbox360 in the graphics dep. Obviously that is not true, but you put a lot of effort into denying any sort of possibility of the inferiority of your system. It reads slightly like f@nboyism. I'm not saying that you aren't impartial, but is there anything that sticks out as a sore thumb on the PS3?
Here's a quick way to explain it. A 3d scene may have 1 million+ verticies in it and the 3d hardware normally processes them all. Thing is, often a huge chunk of those aren't really needed because they are occluded, facing away from the camera, etc. In PS3's case, the spu's in Cell are actually very well suited to looking at the verticies of a scene and throwing away those that aren't really needed. So, Cell basically helps rsx by reducing its workload.
Sounds rather unfair, as the some "weaknesses" of the PS3 have been discussed quite thoroughly (over and over as well...we see it in this thread as well) whereas I can't recall the last time somebody mentioned that of the Xbox360 (nor any details either for that matter). Info on CELL is much more available than for the xbox360's CPU, and as a result, nobody knows how they compare, and likewise for the GPU, where RSX is often comparable to a commercial part. I think nAo offers balance in light of this.
In addition, who are these "other devs", and what credibility to they offer over nAo? For the most part, I think devs, especially, those with more even experience in both machines (or in general?), are usually not the ones to point out advantage in either machine...
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