Uno Venova
Banned
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VGLeaks Rumor: Durango Memory System Overview & Example
- Thread starter Takuya
- Start date
You do have to think about it, though. These aren't PCs with pagefiles... There is physical limits to what you can have in ram. You don't just set and forget.
It's more of an issue if you're dealing with 2 large pools ala PS3
But what are you going to be piping into your ESRam? Think about it. Your rendering pipeline will work in order leaving ESRam free. For some uses you will work with a blank slate every screen refresh... (Ie texturing and shading)... Some uses you will keep it with data in there almost all the time (compute)
In the end you're still managing it as a temporary place for increased performance as opposed to a permanent place where you're competing with every other piece of data that a game requires. Nothing else but those few specific tasks are competing for bandwidth and considering the rendering pipeline is in stages, the tasks should have no latency/bandwidth or allocation issues with each other
gaming_noob
Member
One month and 10 more days. Ugh...
Seriously you need to stop spreading bs, why in the hell would high end GPUs use GDDR5 if DDR3 was better?
The suggestion was that eSRAM + main memory was a simpler setup than just a chunk of main memory.
To the extent that you have to think about data layout and physical memory limits with one chunk of memory, you have to think of the same with two.
It would be even more work if there was latency/bandwidth issues with eSRAM (and, of course, on an upper bound there will be a bandwidth limit to work with).
But I'm not even talking about that. I'm just talking about the simple programmer burden that piping data in and out of eSRAM will require. Deciding what should go there, and when. Deciding how to schedule data movements. This is all a manual process. This is stuff a Durango programmer will have to think about if they want more than 68GB/s of bandwidth at their disposal.
This is all additional thinking a programmer does not have to do with one chunk of memory.
Again, you said:
Maybe I am misunderstanding what you intended to say, but I don't see how this can be the case. There are new subsystems in Durango and programmer will have to learn about (the Move Engine interface), and programmers will have to think about how to map data around the system, across two different pools, and when what data should be in eSRAM, and when to schedule commands to reduce wait-time.
In many ways, it's the kind of mental work that Local Store in Cell required, albeit with a 32MB slate of it. But it is still manual work you're just not going to be doing in a system with one big chunk of memory that has a good deal of bandwidth on its own.
Now, there's simpler and more complex use-cases for eSRAM. Exposure to data juggling between the two pools of data may be limited to specific subsystems (e.g. I can see a lot of games just putting their render buffers into eSRAM and calling it a day, not going beyond that in terms of using eSRAM). But that's sort of besides the point to this argument - that it's a more complex system that requires more attention.
James Sawyer Ford
Member
Right, I don't think anyone is suggesting Durango is hard to develop for...just that it's not as easy as PS4 if the architectures are accurate.
yeah, it just feels it like ppl in this thread are like PS4 ram >>>>>>>>>>>> 720 RAM
where in reality its more like PS4 ram >>> 720 ram
MightyHedgehog
Member
Yeah, you figure that, on top of years of familiarity with split pools of memory with the X360 (and PC, PS2, PS3), they now have more access and flexibility with more and faster ways to access it as well as have coherent and virtualized views on memory and support features and behaviors to make things even easier to manage. I think MS/AMD is going to testbed more of their APU future tech in this new XBOX than they're doing with Sony's machine, almost perhaps debuting the next-gen AMD stuff in the process instead of taking a pumped up current-gen design, like Sony. Obviously, both consoles come from the same tree, but I can see MS favoring the hybridization of theirs and AMD's ideas for next-gen graphics, similar to how they handled X360, but deeper with experience based on Xenon/Xenos. It would be pretty surprising to see a relatively vanilla final hardware design, like the rough outline leaks seem to paint, but those leaks don't seem to say much about equally important features of the architecture that the base specs cannot reveal.
So, yeah, secret sauce, or, rather, just one customer buying the first batch of technology that will feature in the next year's model. After all, other than just being another product and service, XBOX also represents MS' platform showcase for their NUI research and graphics roadmap.
So, yeah, secret sauce, or, rather, just one customer buying the first batch of technology that will feature in the next year's model. After all, other than just being another product and service, XBOX also represents MS' platform showcase for their NUI research and graphics roadmap.
The reason for that is because PS4 RAM bandwith>>>>>>>> 720 RAM bandwith, and rumoured RAM amount free for games is PS4>> 720, so if you put those two together you get PS4 RAM >>>>>>>>>>>720 RAM.
iceatcs
Junior Member
I thought it more likely GDDR5 =< DRR3 + ESRAM (x low latency) is what's going on at the moment
The reason for that is because PS4 RAM bandwith>>>>>>>> 720 RAM bandwith, and rumored RAM amount free for games is PS4>> 720, so if you put those two together you get PS4 RAM >>>>>>>>>>>720 RAM.
how much ram will the ps4 have reserved?
when taken reserved space into account and it ends ups like 720 5gb vs PS4 7gb
then yeah I agree that is a big difference, but at present, an opinion like that seems reaching because we dont know how much ram is reserved for the ps4 and the rumors supporting the 3gb reserved for the 720 are small and sketchy
That's funny, I don't remember Durango being a hard to program for console being a rumor. Could you point towards a link saying that?
Well just the bandwith difference is pretty huge.
dragonelite
Member
Blow the lid off already microsoft the wait is killing me..
isnt that whats the esram and data move engines are for?
I think in 3rd party games the ram wont make the difference, I think esram+data move engine combo will make it competitive with sonys gddr5 memory, sonys may still be better but the ram will not be the part that makes PS4 games look better.
It's really the GPU, and Sony has that in spades for the console space.
Yep.
LukasTaves
Member
The 360's setup is actually not all that similar. On 360 only a part of the gpu had access to the edram, and it was automatic, the developer didn't have to do anything to use it. It did require some custom work to reduce the hit of 720+AA, but in general, developers simply decided not to bother with that, resorting to lower resolutions or no AA if they surpassed the edram size... But even then they benefited from the memory setup.
On durango the entire gpu has acess to the esram, and some orchestration of data is required to make use of the setup... There are some hardware that can help orchestrating this, but only Ms knows how automatically it can actually help.
This very leak implies that the command buffers that the gpu reads come from the data move engines and not directly from the cpu (the DME patent also implied that one of the operations would be to copy data directly from one processor to another)... That alone may require some effort for the developer to synchronize the workflow, otherwise you could end up with both the gpu and cpu stalling waiting for the other.
Actually, I think it will be the other way around. Consoles were the lead platform for most multiplatform games this generation. So much so that any major improvements to the PC version were made after it shipped (high res texture packs, DirectX 11 features, etc).
Psone was very easy to program for yet SCE went for complicated and esoteric architectures in ps2 and ps3. Past history doesn't mean much.
If I remember correctly it was done in a way that it would make porting to the other consoles not worth the trouble.
phosphor112
Banned
I don't see how MS's work with AMD is a test bed for their future chips. Especially with eSRAM on there. No chip for any PC ever comes with embedded ram. None. Because it's expensive and hot. It's honestly useless for consumers. Embedded RAM is used to make up for bandwidth deficiencies, which Sony's design does not have (and frankly, 68 GB/s from the Durango is much higher than any PC's DDR3 speeds are). Not only that, but AMD already said they are selling a lighter version of the PS4's APU. It might be because PS4 was announced first, but the design would resemble PS4's more than Durango's anyway.
As I stated above, embedded RAM is used to make up for bandwidth deficiencies. The combined speeds of both the main and eSRAM won't be as high as the GDDR5 in the PS4. Also, the Move Engines don't increase bandwidth, and are in fact, limited by the speeds of the DDR3 (this was not only speculated, but confirmed by the VG Leaks rumor in this very thread).
The ESRAM is quite small really at 32 MB so while it can help it certainly won't do wonders. Data move engines might be a bit helpful but it's nothing spectacular. Plus the work that will have to go into writing the code to get the data from main RAM to ESRAM or Data Move engines and retain it there until it is needed will make it more difficult to programme for than PS4.
PS4's RAM solution is a very lucky, educated guess by Sony. They always wanted high bandwith and unified RAM solution. They started with 2GB when that was all that could be achieved with those goals in mind. They switched to 4GB when the new chips became available and got super lucky that newer chips are available now which allowed them to to 8GB without any difficulty and while maintaining their design philosophy.
MS went a completely different route. MS wanted to have A LOT of RAM no matter the drawbacks and at the time when the console was being designed 8GB seemed like a thing that would be unmatched. However, they had to design their whole system around the drawbacks of chosing DDR3 RAM with the Data Move engines and ESRAM (they even seemed to have chosen a lesser GPU,since, presumably, a higher one wouldn't really benefit from the slow RAM). While these boosters might help a bit they certainly can't match the bandwith of PS4's GDRR5. Maybe MS was counting on the fact that chip densities that would allow Sony to go 8GB won't be available when PS4 will launch and this gamble backfired.
googleplex
Member
No! The latency of GDDR5 has been completely overblown by people desperately looking for parity between both consoles.
uncledonnie
Banned
I really doubt this was even a factor in their design.
Well yeah I was only thinking out loud. But honestly MS must have thought 8 GB was enough for both their resource heavy focus on apps and multimedia and games.
googleplex
Member
No where back to believing in mathematics and physics. The 720 is looking like it will be a hell of a machine, and a huge step up over its predecessor. But the PS4 is looking like a step(or half a step) above that.
Sure, but that doesn't mean "the latency of GDDR5 has been overblown". What numbers are you relying on for that assertion? Why are they different than vgleaks? There is no reason that both statements cannot be true: PS4 is more powerful than Durango and GDDR5 latency is significantly worse
Latency isn't an issue, even if GDDR5 has a huge amount more than DDR3 and eSRAM. It's easily compensated for on both the hardware and software end, especially in an APU designed around utilizing GDDR5.
H_Prestige
Banned
It won't be any where near 2-3GB reserved, considering Sony was about to go with 4GB GDDR5 until the last minute. My guess is 512MB reserved for OS, maybe 1GB at most.
googleplex
Member
Way overblown in both significance and impact.
This sounds identical to the magic efficiency that is supposed to make Durango ignore all other bottlenecks
I'm guessing 1gb at launch in case they decide to add anything since they have more RAM to work with now and maybe opening more up if necessary as time goes on. No one's going to be using 7gb or more for a while.
1GB is likely and 1.5GB at worst. It'll be better to cordon off a section for potential future-proofing. In any event, if they don't need it, they can always give it back to the devs (a la PS3).
I want to see what they're up to as well. I fail to believe for a second that they're going to let Sony have them caught with their pants down thinking they were only going with 4GB RAM in which allowed MS to do 8GB and have a larger reserve for other possibly non-gaming functions.
Someone (probably Epic, who "showed them why to go 512mb" last gen lol) had to of leaked to them what Sony was up to again.
Yeah. I don't think Microsoft's focus has been on hardcore gaming for a while now. I think their key goal is to produce a home entertainment system that caters for all the family's needs.
I've been posting this stuff over B3D, but AMD has a new part supposedly to be coming in April, the "Bonaire" or 7790 GPU. It's supposed to slot between 7770 and 7850 on PC's.
Notable things about this guy are, it sports 768 SP's. Which is 12 CU's. In other words exactly what Durango is rumored.
http://translate.google.com/transla...radeon-hd-7790-bonaire-i-sweclockers-testlabb
Another thing is, it seems to be possibly clocked at 1075 mhz stock. The link calls it a overclocked model, but every spec sheet I've found claims 7790 is clocked at 1075 period (for example this link http://www.tomshardware.com/news/AMD-Radeon-7790-Saturn-GPU,21447.html ). Additionally a lot of links claim AMD wont allow overclocked 7790 so as not to encroach on 7850. Which would mean they all have to be the same clock.
So if 1075 is stock, I'm really hopeful for a Durango clock bump to at least 1 ghz.
There also seems to be some claims Bonaire is GCN 2.0, which is also interesting. If it's the same as PS4 it probably doesnt mean a lot though. It wouldn't surprise me.
Also another thing pointed out on B3D, 7790 spec sheet lists:
Is exactly the same as the Durango ESRAM BW I think. A little odd/coincidental anyway.
Hmm. So maybe the esram is there and tuned for best performance with the GPU, then surrounded by various mo e engine gubbins to mask/mitigate the DDr3?
Any info on triangle setup/geometry engines?
Not sure what GCN2 is supposed to bring other than being on 28nm, in which case would PS4 be GCN2 by default?
phosphor112
Banned
There's a reason GDDR5 has been standard on GPUs for years now. RAM latency is measured in nano seconds so even if there's twice as much latency on GDDR5 it's still a minute amount of time. No devs have expressed concern over GDDR5 latency either.
Pretty much. CPU's generally have enough cache so it's not a big issue. Essentially if you're missing the cache THAT often you're doing it wrong. The higher latency means that negative effects of any cache miss will probably be greater (more missed cycles) but that's about it. High latency also has extremely minor performance issues for GPUs due to the nature of the datasets and workloads the GPU's use. Again prefetching and caching on the GPU side eliminates most of the negative effects of higher latency.
Rumor might have been the wrong word to use as i took this from gaf speculation .
However my point still stands,
From the time i have been lurking here you have jumped on every possible piece of info that was presented here no matter how unlikely or impossible it was(dual gpu, dual cpu , special sauce, wizard jizz,a spec update 1 year before release etc.. ) and have given( or at leastclaimed that you did ) each and every one a chance to be true or false.
now based on leaks(that may or may not be accurate but for the sake of this argument lets assume that they are) and lots of GAF tech analysis it may be that durango may be more difficult to develop compared to the ps4 in terms of memory.
However when that notion was presented to you ,you dismissed it outright claiming MS is not making a difficult console to develop for, period based on previous console efforts, but
PS3 and currently wii u has shown that to be meaningless.
why not give this notion a fair chance then ?
Why not consider this "what if..?"
ChosenPredator
Banned
as an outsider just viewing this thread and not knowing that much about tech specs but knowing the history of MS being easy to develop for ...it's odd that it would be suddenly difficult...i mean the devs have dev kits now right? you'd figure they'd have some input on it.
If it's a rumor I'll give it a chance. But there is no documentation of Durango being hard to program for from developers.
Uno Venova
Banned
The only thing I remember is edge saying that durango has a more oppressive operating system overhead that the PS4. I would like a analysis on it's own and how it compared to past consoles.
Tripolygon
Banned
If you've never seen any graphics card comparison where memory latency is compared or used as a bottleneck then STFU about latency. It doesn't matter.
phosphor112
Banned
I wouldn't say it's hard, but it's definitely harder than the PS4.
Remember most of the challenge of deving on the PS3 was poor documentation to the Western audience.
Same with PS2.
With proper tools and documentation, the growing pains of developing games on either console will be lessened.
First off, companies, especially Middleware companies, cannot and will not leak the plans of one console maker to the other, just because a few posters on GAF wish they did.
Secondly, not even Sony's first parties knew about the bump to 8GB before February 20th.
So no, MS did not know. And even if they do now, it's far too late to change anything substantial.
Yup, thus the worse GPU design and the complicated setup to get that 8GB of RAM in, since MS didn't believe the GDRR5 chip densities could be ready for a 2013 launch. There's also some rumors of MS wanting to launch last year and deciding against it.
Whoops, sorry!
well 1.84 vs 1.23 a 600gflop difference will produce small differences, we're talking superior anti analyzing and slightly more and better effects
it will be nothing like and xbox vs ps2 scenario sombody mentioned in one of these threads.
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