• Hey, guest user. Hope you're enjoying NeoGAF! Have you considered registering for an account? Come join us and add your take to the daily discourse.

AMD: PlayStation 4 supports hUMA, Xbox One does not

ElTorro

I wanted to dominate the living room. Then I took an ESRAM in the knee.
Article from Germany's biggest and very reputable IT news site, found by Junior W!CKED:

http://www.heise.de/newsticker/meld...et-Unified-Memory-Xbox-One-nicht-1939716.html

My translation:

Although both upcoming game consoles Xbox One and PlayStation 4 are based on AMD hardware, only PlayStation 4 incorporates hUMA [Heterogeneous Uniform Memory Access] for supporting a shared memory space. This was explained by AMD's Senior Product Marketing Manager Marc Diana to c't [big German IT magazine] at gamescom. This should put the 3D-performance of PlayStation 4 much farther ahead of Xbox One than many have expected so far. AMD sees hUMA as a key element for drastic performance improvements in combined processors. AMD's upcoming Kaveri desktop processors support hUMA as well.

Behind the scenes, c't could hear from developers that the 3D-performance of PlayStation 4 is very far ahead of Xbox One.

Back in April, AMD manager Phil Rogers explained to c't that hUMA improves 3D-performance in particular. "Game developers have been eager to use very large textures for years. Until now they had to resort to tricks in order to package parts of larger textures into smaller textures. That is because today a texture has to be located in a special place of physical memory before the GPU can process it. With hUMA, applications can work with textures much more efficiently". AMD will give more details on hUMA at its upcoming developer conference in November.

Update 1:

hUMA: Heterogeneous Uniform Memory Access (Yes, people already made tons of "sense of hUMA" jokes)
http://arstechnica.com/information-...orm-memory-access-coming-this-year-in-kaveri/

Even with the integration of GPUs and CPUs into the same chip, GPGPU is quite awkward for software developers. The CPU and GPU have their own pools of memory. Physically, these might use the same chips on the motherboard (as most integrated GPUs carve off a portion of system memory for their own purposes). From a software perspective, however, these are completely separate.

This means that whenever a CPU program wants to do some computation on the GPU, it has to copy all the data from the CPU's memory into the GPU's memory. When the GPU computation is finished, all the data has to be copied back. This need to copy back and forth wastes time and makes it difficult to mix and match code that runs on the CPU and code that runs on the GPU.

The need to copy data also means that the GPU can't use the same data structures that the CPU is using. While the exact terminology varies from programming language to programming language, CPU data structures make extensive use of pointers: essentially, memory addresses that refer (or, indeed, point) to other pieces of data. These structures can't simply be copied into GPU memory, because CPU pointers refer to locations in CPU memory. Since GPU memory is separate, these locations would be all wrong when copied.

hUMA is the way AMD proposes to solve this problem. With hUMA, the CPU and GPU share a single memory space. The GPU can directly access CPU memory addresses, allowing it to both read and write data that the CPU is also reading and writing.

hUMA is a cache coherent system, meaning that the CPU and GPU will always see a consistent view of data in memory. If one processor makes a change then the other processor will see that changed data, even if the old value was being cached.

As well as being useful for GPGPU programming, this may also find use in the GPU's traditional domain: graphics. Normally, 3D programs have to use lots of relatively small textures to apply textures to their 3D models. When the GPU has access to demand paging, it becomes practical to use single large textures—larger than will even fit into the GPU's memory—loading the portions of the texture on an as-needed basis. id Software devised a similar technique using existing hardware for Enemy Territory: Quake Wars and called it MegaTexture. With hUMA, developers will get MegaTexture-like functionality built-in.

Update 2:

Well explained:

On a classical system you have a RAM pool and a VRAM pool that are physically speperated. Copying data from one pool to the other creates latency. The GPU is very good ad hiding latency. What it needs most is high bandwidth. The CPU on the other hand is extremely sensitive to latency. The CPU needs extremely low latency to work efficiently. Copying data from the RAM (CPU) to the VRAM (GPU) creates latency, but that's okay for the GPU. Copying data from RAM (CPU) to VRAM (GPU) and back to the RAM (CPU) creates even more latency. It's too much for the CPU. The copying alone takes longer than the computation wich makes this roundtrip highly ineffective.

Xbox360 and older APUs have a unified RAM. This means that the RAM is no longer physically seperated, but even though it's the same RAM chips, the system still distincts between memory partition for the differenct processors. You still need to copy the data between CPU partition and GPU partition, but this will be much more efficient than copying it between physically seperated pools. But it's still too much latency for a CPU, GPU, CPU roundtrip.

PS4 will have hUMA wich means that you no longer need a distinction between CPU partition and GPU partition. Both processors can use the same pieces of data at the same time. You don't need to copy stuff and this allows for completely new algorithms that utilize CPU and GPU at the same time. This is interesting since a GPU is very strong, but extremely dumb. A CPU is extremely smart, but very weak. Since you can utilize both processors at the same time for a single task you have a system that is extremely smart and extremely strong at the same time.

It will allow for an extreme boost for many, many algorithms and parts of algorithms. On top of that it will allow for completely new classes of algorithms. This is a game changer.

Update 3:

Further evidence: Sony joined the HSA (Heterogeneous System Architecture) Foundation originally co-founded by AMD while Microsoft has not:
http://hsafoundation.com

Update 4:

The summary so far:

To summarize the evidence so far: we have an article from a respected source, echoing Senior Product Marketing Manager Marc Diana in saying that PS4 implements their hUMA architecture while the XB1 does not. This is followed by the deduction that PS4 will have a significant performance boost over XB1 because of that. It remains unclear what the AMD representative said verbatim. We can only say that c't is as reputable as it gets in the space of German IT publications; that does not make them infallible, of course.

In addition, Sony is part of the HSA consortium while Microsoft is not. Of course, we don't know the political implications of such a membership which may play a significant role along purely technological reasons.

Technology-wise, we can say with certainty that PS4 indeed is a hUMA architecture. Everything we have heard since the release from official sources, especially PS4's Onion/Garlic memory bus layout and the volatile tag on cache lines, confirms that. In addition, Sony has actually advertised this fact quite aggressively, beginning with the Havok GPGPU demo at the PS4 reveal.

We don't know much what the Xbox One does beyond what the leaked documents tell us. And those are ambiguous and not very detailed. At first, it sounds unexpected for it to not support hUMA. Microsoft certainly has implemented a more custom memory system than Sony to manage its DDR3/ESRAM layout, including its DMEs. There is no clear indication about which features of a hUMA architecture might be lacking. Maybe not all memory clients and pools are cache-coherent system wide. The GPU does seem to have to flush its caches when it synchronizes with other clients. However, the article on vgleaks is neither very detailed nor clear, nor do we know if its author recited the original sources correctly. So the relationship between a hUMA feature set and the XB1 is unclear.

Politics-wise, AMD certainly wants to push hUMA since it is part of its own upcoming end-customer products. This would be reason alone to champion the PS4 independent of what the XB1 does, since AMD won't profit from what Microsoft has done with its memory subsystem.

Apart from that, developers at gamescom seem to acknowledge anonymously that the PS4 has a clear 3D-performance advantage over the Xbox One which is certainly a result of many factors, not least because of its beefier GPU and its straight-forward, high-bandwidth GDDR5 setup.

Update 5:

Got a response from the author of the heise.de article.

Edit: Article is accurate as it is presented.

http://en.wikipedia.org/wiki/C't on the magazine that did the interview:

c't – Magazin für Computertechnik (magazine for computer technology) is a German computer magazine, published by the Heinz Heise publishing house. Originally a special section of the electronics magazine elrad, the magazine has been published monthly since December 1983 and biweekly since October 1997. […]

The magazine is the second most popular German language computer magazine with a sold circulation of about 315,000 (as of March 2011; printed circulation: 419,000). With 241,000 subscriptions it is the computer magazine with the most subscribers in Europe.

Update 6:

The Verge reported back in June on all topics AMD and seems to have included the XB1, although we haven't, again, a direct quote.

That might sound suspiciously vague, but we spoke to AMD and it's actually true. The AMD chips inside the PlayStation 4 and Xbox One take advantage of something called Heterogeneous Unified Memory Access (HUMA), which allows both the CPU and GPU to share the same memory pool instead of having to copy data from one before the other can use it. Diana likened it to driving to the corner store to pick up some milk, instead of driving from San Francisco to Los Angeles. It's one of AMD's proposed Heterogeneous System Architecture (HSA) techniques to make the many discrete processors in a system work in tandem to more efficiently share loads.

http://www.theverge.com/2013/6/21/4452488/amd-sparks-x86-transition-for-next-gen-game-consoles

Update 7:

Apparently, AMD's spokesperson was not supposed to say what he said, so AMD dismissed having said anything.

During a recent Gamescom 2013 interview, an AMD spokesperson made inaccurate statements regarding the details of our semi-custom APU architectures.
AMD will not comment on the Microsoft Xbox One and Sony PS4 memory architectures and will not speak for Microsoft, Sony or other AMD customers.

Update from the Heise author:

He had a phone call with AMD and he says that they left open whether Marc Diana's statements are true or untrue. He also says that AMD made pretty clear that they're not allowed to talk about PS4 or Xbox One

"AMD ließ auch während eines Telefongespräches offen, ob die Behauptungen von Marc Diana der Wahrheit entsprechen oder nicht. Besonderen Wert legte das Unternehmen vor allem auf die Aussage, dass die Firma keine Aussagen zu den Produkten seiner Kunden treffen darf – also auch nicht zu Sonys Playstation 4 oder Microsofts Xbox One."

http://www.heise.de/newsticker/meld...et-Unified-Memory-Xbox-One-nicht-1939716.html
 

ElTorro

I wanted to dominate the living room. Then I took an ESRAM in the knee.
Haven't looked into it in depth but it might because of ESRAM.

Think so as well. ESRAM might be an obstacle in ensuring cache coherency and implementing unified memory controllers in general.
 

gofreak

GAF's Bob Woodward
I thought this was the more interesting bit in terms of actual results today, if it's the noise going around Gamescom:

Behind the scenes c't could also capture developers unofficial voices that see the 3D performance of the Playstation 4 very far from that of the Xbox One.
 
I thought this was the more interesting bit in terms of actual results today, if it's the noise going around Gamescom:

Our guy on the ground has heard this as well from multiplatform developers and publishers. Their PS4 game builds are significantly outperforming the Xbox One game builds.
 

Rat Salad

Banned
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.
 

XeNoN89

Banned
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.

These are launch games, I suspect the differences will begin to become more noticeable around this time next year
 

beast786

Member
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.

definitely on topic.

Thanks OP for posting
 

ElTorro

I wanted to dominate the living room. Then I took an ESRAM in the knee.
The translation is horrible, sorry for that. I'll make one myself.
 

omonimo

Banned
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.

Launch games tell you the console capability? Are you joking? Only from 2 - 3 years we can see something of concrete.
 

benny_a

extra source of jiggaflops
This can't be right. The Xbone isn't hUMA? That's what makes the architecture next-gen over what the 360 offered.
 

gofreak

GAF's Bob Woodward
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.

I think the developer commentary the article refers to is from third parties working on multiplats. We've not yet been able to compare multiplats on these systems for ourselves.
 

Damian.

Banned
It's looking more and more like a Dreamcast vs OG Xbox comparison. If true, then MS is going to be screwed this generation.
 
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.

The difference will become more visible as next gen goes on, it'll probably end up just like ps2 and xbox(look at the splinter cell games).
 

Tiglet

Banned
So we have PS4 vs Xbox = 80%(*2 according to this story) = 160% more powerfull and we have PS4 vs Overheating Xbox = 200% (*2 according to this story) = 400%.

Goddamn.
 

twobear

sputum-flecked apoplexy
It's looking more and more like a Dreamcast vs OG Xbox comparison. If true, then MS is going to be screwed this generation.
...have you actually seen the games? There are differences in favour of PS4 but there is not a Dreamcast to Xbox type power discrepancy here.
 

inner-G

Banned
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.
They look exactly the same when your head is buried in the sand.
 

gruenel

Member
My attempt at a rough translation of the first two paragraphs (still better than Google translate I guess):

Although there is AMD hardware in both upcoming consoles, the Xbox One and the PS4, only the PS4 will support hUMA technology for a shared memory pool. This was explained by AMD's Senior Product Marketing Manager Marc Diana in conversation with c't at Gamescom. This should put the PS4 even more ahead of the Xbox One in terms of 3D performance than what is currently assumed. After all, AMD is looking upon hUMA as the key for unlocking a huge amount of processing power in combined processors (APUs). AMD's upcoming Kaveri desktop processors also support hUMA.

Behind the scenes, c't has heard inofficial remarks from developers who said the 3D performance of the PS4 is way ahead of the Xbox One.

The last paragraph is just some stuff about hUMA in general and how it can be used to improve texturing, can't be bothered to translate that right now.
 
why can't the Xbone have hUMA? isn't their memory unified? (8GB) albeit DDR3

no. that ESRAM in the xbone is required because the DDR3 is so low bandwidth. That mitigates the bandwidth problems, but prevents hUMA from being usable.

makes sense, but MAN this is bad news for microsoft and xbox fans. The ps4 is going to be the definitive version of every single console multiplatform, no exceptions.
 

JaggedSac

Member
Interesting, MS was part of a group pushing for hUMA if I recall correctly. Wonder why they didn't push for that.

no. that ESRAM in the xbone is required because the DDR3 is so low bandwidth. That mitigates the bandwidth problems, but prevents hUMA from being usable.

I also thought the Bone GPU had direct access to RAM if it wanted, thus hUMA would still be useful.
 
Digital Foundry articles will be interesting, they have been dismissed by some of late on here, bias and so forth. Lets see the response to their verdicts this coming gen.
 

Toski

Member
...have you actually seen the games? There are differences in favour of PS4 but there is not a Dreamcast to Xbox type power discrepancy here.

The problem is MS giving advantages to Sony. PS4 already has a raw numbers advantage, adding architectural advantages will further the gap.
 

strata8

Member
hUMA doesn't have much to do with GPU performance unless you're talking about GPGPU. It's certainly not going to do anything for 3D rendering like the article implies.
 
At this point i think some here would probably commit suicide if they couldnt go another day without dick waving. :) But the games on both machines tell a different story. Theres no huge jump from one to the other. Both machines look like they could easily pull off the same visuals should their exclusives ever trade places.
Why so defensive? I've noticed a trend with your posts lately.
 

ElTorro

I wanted to dominate the living room. Then I took an ESRAM in the knee.
hUMA doesn't have much to do with GPU performance unless you're talking about GPGPU. It's certainly not going to do anything for 3D rendering like the article implies.

They are not only talking about GPGPU but apparently also about textures.
 

Madness

Member
Oh man, here comes a new thread every day that will use "hUMA" as a measurement about how one console is better than the other.

'but it doesn't have any hUMA', 'dude, it only has half the hUMA' etc.
 

gofreak

GAF's Bob Woodward
From what we know GPU can access DDR3 in Xbone and i'm pretty sure it has hUMA too. Writer probably misunderstood.

I started to read the tomshardware article linked earlier, and already the first criteria isn't met by Xbox One.

i.e.

"Coherent Memory: Ensures that CPU and CPU caches both see an up-to-date view of the data"

On Xbox One you have to flush GPU cache for modified data to become viewable on the rest of the system.

IIRC on PS4, there are different ways to synchronise CPU/GPU views of data without having to flush GPU caches.

Overall the Xbox One memory/bandwidth setup is a lot less simple than PS4's - more than one pool of memory, different coherency characteristics, lots of different buses. Maybe it does not technically meet AMD's definition for hUMA because of those complications.

These consoles use Jaguar CPUs and GCN GPUs. Jaguar + GCN APUs (Temash, Kaveri, Kyoto) don't have hUMA.

HUMA is a feature that will debut on PC in 2014 (Kaveri). So, my guess is that Sony paid AMD to integrate this feature into PS4 while Microsoft didn't.


Sony did add in extra bus/cache features, 'Onion+', which I think are due in the next APUs.
 
Let's see if the developers other than sony's first party can takr advantage of this.

Yep. PS3 was more powerful and nobody but 1st party took advantage. I hope we'll see some big differences in performance with open world games, racing games, etc ... ones that really benefit from having a more powerful system , but with games parity on the systems regarding developers I'm not hopeful.
 

omonimo

Banned
Oh man, here comes a new thread every day that will use "hUMA" as a measurement about how one console is better than the other.

'but it doesn't have any hUMA', 'dude, it only has half the hUMA' etc.

I think just the GDDR5 is enough to beat the other.
 
Top Bottom