Xbox One: DirectX 11.1+ AMD GPU , PS4: DirectX 11.2+ AMD GPU what's the difference?

[SlimJim]

Look, computing cores are probably almost identical if not identical for both X1 and PS4 and general feature set is definitely a close match in both cases (multitasking, 3D and compute, tesselation and everything one would expect from a modern GPU). Both are 11.2 for sure. Those pluses usually mean some extra stuff that's not exposed through regular 11.2 interfaces. Stuff like mappable SRAM would be that. Some new texture compression format would be in the "+" space. Custom filtering for, say, shadows' PCF would be in the "+" space. It's not PR, it's "these are 11.2 GPUs with some additional/custom stuff we can't talk too much about". Some changes that happened recently were well grounded in math. If you bump up the core speed, you get extra power. The memory controller case is curious but not impossible - driver code* tends to abuse HW design in many cases. You do this whenever you can to gain some advantage. Programmers have done this for ever - take C64 and sprites on the screen border. This has nothing to do with PR but I'm pretty sure that you wouldn't have a clue how HW is being exploited even if you got all the technical details on a silver platter. If it's PR for you - fine. But being ignorant in the "Console Technology" section is something that won't get you far around here.

* consoles have no drivers, they have thin code layer that mostly hides HW issues from the game developers and exposes nice and familiar interfaces to them

Thanks for taking your time to elaborate on the subject, I respect that.

I know that in the case of the 360, using embedded ram significantly helped with transparency effects (for example) because of the extra bandwidth. So I understand that it was a great advantage.
However, if the main (graphics) ram had an even higher speed than the embedded ram, then the use of embedded ram+'slow' memory would not be an advantage against just using even faster than embedded ram-memory. (I hope you understand my point)

 

[Dominik D]

It would be an advantage because SRAM is still much faster than GDDR5 used in PS4 (and it has lower latency too). This won't make the texture reads faster (although texture locality combined with proper texture unit caches alleviate the pain significantly) it won't help with vertex/index buffer reads but it will help with everything that has to do with dependent renders. Deferred rendering is a prime example. Shadowing would probably also benefit. The problem 360 had was the size of embedded memory - it was too small to keep all the temporary data. To use it you'd have to use tiling (dividing screen into smaller parts and rendering them separately) but this (I'm simplifying here) adds to the cost of vertex processing. So tiling was probably rarely a win. This e.g. lead to lower res games. So again thing that you're trying to ignore all this time: there are scenarios where (I'll exaggerate a little to make it more obvious) small, fast memory combined with big slow memory will be better in certain scenarios than one big, medium speed memory. I've given you examples of such cases and stated clearly that every design decision has both benefits and drawbacks. Because technology is about trade-offs, not about ticks on the box and raw numbers.

 

[Shifty Geezer]

This is not, nor is there anywhere on this board, a 'which console is best' thread. The OP was answered - there's no difference because DX11.2 doesn't require different hardware to DX11.1.

 

[Shifty Geezer]

Thread reopened by request of DaveB. This is not a versus/comparison thread beyond the technical differences of the GPU and what DX11.x means.

 

[Dave Baumann]

While the naming of DX11.2 is a bit of a head scratcher (it doesn't actually need to have Feature level 11_1 capabilities, so GPU's that don't even have full DX11_1 can claim to be DX11.2 GPU's), note that probably the primary 3D feature of interest is indeed tiled resources, which comes in two tiers. I just want to draw the technically inclined to a nuance in the recent statement concerning support:

The Radeon™ HD 7000 series hardware architecture is fully DirectX 11.2-capable when used with a driver that enables this feature. AMD is planning to enable DirectX 11.2 with a driver update in the Windows® 8.1 launch timeframe in October, when DirectX® 11.2 ships. Today, AMD is the only GPU manufacturer to offer fully-compatible DirectX 11.1 support, and the only manufacturer to support Tiled Resources Tier-2 within a shipping product stack.

 

[astrograd]

Tier 2 Tiled Resources?

 

[Mianca]

Tier 2 Tiled Resources?

As far as I can see, "Tier 2 Tiled Resources" basically refers to "Partially Resident Textures" as implemented on the basis of DX 11.1 capable hardware.

(However, Partially Resident Textures can also be done on DX 11.0 hardware - and that kind of implementation seems to be referred to as "Tier 1").

The gist seems to be that DX 11.1+ hardware capability is more important than DX 11.2 feature compatibility.

 

[SlimJim]

So... you are saying they are actually not the same?

 

[eVolvE]

First post, and I hope I can contribute.

What it means is, that any DX11.1 AMD graphics hardware on the market today(HD7000+) and any future console hardware (PS4, XO) is capable of achieving DX11.2 features. Since these new DX11.2 features can simply be enabled in software (via drivers) and do not require new hardware capabilities.

Therefore, DX11.1+ effectively becomes DX11.2+ once the drivers have been updated to accommodate that enhanced feature set provided by DX11.2.

In short: hardware-wise - not different, software-wise - different (but can be enabled via driver updates)

 

[Dave Baumann]

Read the quote again.

 

[Shifty Geezer]

What it means is, that any DX11.1 AMD graphics hardware on the market today(HD7000+) and any future console hardware (PS4, XO) is capable of achieving DX11.2 features.

Not quite (that was my point when I first closed the thread, which Dave wanted to correct). DX11.2 requires Tiled Resources Tier-2 which currently only AMD supports in its current products, and DX11.2 requires a hardware feature that isn't present in all 11.1 devices (nVidia's DX11.1 cards won't be updateable).

That says nothing about the hardware in PS4 and XB1 though, which we can assume have the same required featureset but maybe don't. With PS4 explicitly stating DX11.2 compatibility, I assume it has the required features. With XB1 presently saying 11.1, there's the possibility of it not supporting this feature, though that seems improbable. grndzro says GCN has been reported as DX11.2 compatible. Ah yes, DirectX 11.2 was reported as a Windows 8.1 and XB1 exclusive update. So there we go, both consoles support DX11.2 on the hardware level.

 

[eVolvE]

I explicitly state AMD hardware in my post and am well aware that nVidias hardware can not achieve it yet.

You're right that we don't know for sure, but MS mentioned DX11.2 featureset exclusivity for Windows 8.1 and Xbox One during this years Build Conference. They even demoed Tiled Resources there.

 

[onQ]

I explicitly state AMD hardware in my post and am well aware that nVidias hardware can not achieve it yet.

You're right that we don't know for sure, but MS mentioned DX11.2 featureset exclusivity for Windows 8.1 and Xbox One during this years Build Conference. They even demoed Tiled Resources there.

Some times you have to watch the wording of on stage presentations because he could have been only talking about the Tiled Resources when he mentioned the Xbox One & not DirectX 11.2.

.

 

[Shifty Geezer]

You're right that we don't know for sure, but MS mentioned DX11.2 featureset exclusivity for Windows 8.1 and Xbox One during this years Build Conference. They even demoed Tiled Resources there.

Yes, I recognise as much. My post contains a thought stream as I looked some stuff up online.

 

[Hecatoncheires]

Not sure if you knew it, but the context of Sony's "DX11.2+ feature set" claim was that they managed to use a form of sparse voxel global illumination on PS4 that uses sparse textures instead of octrees:

 

[willardjuice]

Some times you have to watch the wording of on stage presentations because he could have been only talking about the Tiled Resources when he mentioned the Xbox One & not DirectX 11.2.

.

No, tiled resources is basically the main selling point of Direct3D 11.2. It's either supported through a software implementation (tier 1) or a hardware implementation (tier 2). Tier 2 is essentially what AMD calls "Partially Resident Textures" and is available on all GCN based architectures ("real" 7xxx cards, xb1, ps4, etc.). Imo, Direct3D 11.2 was created so that devs can use PRT on consoles and still back port it to their PC builds. If you're AMD, this is what you are hoping for!

Thus evolve is correct. All 11.1 AMD cards can be upgraded to 11.2 (with tier 2) through a driver update. Since only AMD cards support PRT, they are the only IHV with tier 2 support (atm). Nvidia can update their 11.0 cards to support the new software features in 11.2, but not tier 2. The same applies to Intel's 11.0/11.1 igps. I also assume the same applies to VIA's 11.0 hardware (but who cares about VIA right?).

You can see why Dave/AMD is pushing tier 2 support...

 

[Dave Baumann]

Still not got it.

 

[blakjedi]

Support for 11.2 is not based on 11.1 capabilities or support. You can have a device that's not fully 11.1 compliant but said to support 11.2. Only hd7000 natively supports the entire dx11 stack regardless of whether the features are revealed though drivers or not.

Also 11.2 wont even exist until after October when MS makes it "available".

 

[Scott_Arm]

Still not got it.

I don't get the significance of the bolded within.

 

[bbot]

Still not got it.

Hardware page lookup table is in the Xbox One gpu, but NOT in the PS4 gpu?