AMD Radeon HD 7000 Series getting DX11.2 Support. Kepler Support Better Explained.

Usually between revisions of DirectX, such as from 10 to 11, there are major changes in the underlying API/code.  With the latest service packs, patches, what not, this has not normally been the case.

DX11.1 and 11.2 were mostly software side optimizations, however, the Radeons do have full hardware support even for the optional feature sets in DX11.1/2 (optional as declared by Microsoft not nVidia ;)  In AMDs case, they really could be driver side supported.  AMD is showing this by releasing support for up and coming DX11.2 (via Windows 8.1) in a driver update.

"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.”

Pcper: http://www.pcper.com/news/Graphics-Cards/GCN-Based-AMD-7000-Series-GPUs-Will-Fully-Support-DirectX-112-After-Driver-Updat
MaximumPC: http://www.maximumpc.com/driver_update_will_add_directx_112_support_amd_radeon_hd_7000_series_gpus


What AMD stated is pretty much true, roughly 90% was software side and they have the ability to support the extra 10% with dedicated hardware.

According BON (Brightside of the News), who first reported that the HD 7000 series supposedly would support DX11.1 by hardware, nVidia weighed in on the situation then.  There were four features left out, on Kepler's side, that nVidia stated they didn't think they pertained to gaming.

nVidia's Quote:

"The GTX 680 supports DirectX 11.1 with hardware feature level 11_0, including all optional features. This includes a number of features useful for game developers such as: 

• Partial constant buffer updates 
• Logic operations in the Output Merger 
• 16bpp renderingUAV-only rendering 
• Partial clearsLarge constant buffers 

We did not enable four non-gaming features in Hardware in Kepler (for 11_1): 

• Target-Independent Rasterization (2D rendering only)
• 16xMSAA Rasterization (2D rendering only) 
• Orthogonal Line Rendering Mode 
• UAV in non-pixel-shader stages 

So basically, we do support 11.1 features with 11_0 feature level through the DirectX 11.1 API. We do not support feature level 11_1. This is a bit confusing, due to Microsoft naming. So we do support 11.1 from a feature level for gaming related features."

From my understanding, I looked up what exactly was Microsoft's naming convention.  It looks like 11_0 was released with DirectX 11.  Code specific to ONLY 11.1 was deemed 11_1.  They then went on to state that they do support the 11_0 (which is apart of DX11.1) but not 11_1 via the 10% that require specific hardware.  It is somewhat confusing on Microsoft's side, but to me it seems nVidia is trying a little damage control.

So to my original statement, most of the DX11.1 was software updates, therefore, should run on DX11.0 hardware.  You can not do the same for an entire family revision (ex DX12).  These DX11_1 features not included via hardware, could very well be included with work around for developers in the driver (call this function for this effect etc.).  The same can be said of the DX11_2 release.  There is not much in the way of substantial change.

Source: http://www.brightsideofnews.com/news/2012/11/21/nvidia-doesnt-fully-support-directx-111-with-kepler-gpus2c-bute280a6.aspx

It is all still rather more straightforward on AMDs side the nVidia, but I did find this immensely helpful breakdown on Anandtechs Forums.

OK. Enough with this kind of misunderstanding.
Let's see the facts:
- DX11.2 will be supported by any DX11 or DX11.1 GPUs.
- Tiled Resources support is not mandatory, it's just an option.
I created a list that contains the most relevant gaming features in DX11.1/11.2 and the hardware support for it.

Mandatory features:
Logic operations in the Output Merger:
NVIDIA Kepler: Yes
NVIDIA Fermi: Yes
AMD GCN: Yes
AMD VLIW4/5: Yes
Intel Gen7.5: Yes
Intel Gen7: No

UAV-only rendering:
NVIDIA Kepler: Yes
NVIDIA Fermi: Yes
AMD GCN: Yes
AMD VLIW4/5: Yes
Intel Gen7.5: Yes
Intel Gen7: Yes

UAV in non-pixel-shader stages:
NVIDIA Kepler: No (technically yes, but the DX limit this option in feature_level_11_0)
NVIDIA Fermi: No (technically yes, but the DX limit this option in feature_level_11_0)
AMD GCN: Yes
AMD VLIW4/5: No (technically yes, but the DX limit this option in feature_level_11_0)
Intel Gen7.5: Yes
Intel Gen7: No

Larger number of UAVs:
NVIDIA Kepler: No (8)
NVIDIA Fermi: No (8)
AMD GCN: Yes (64)
AMD VLIW4/5: No (8)
Intel Gen7.5: Yes (64)
Intel Gen7: No (8)

HLSL FLG:
NVIDIA Kepler: Yes
NVIDIA Fermi: Yes
AMD GCN: Yes
AMD VLIW4/5: Yes
Intel Gen7.5: Yes
Intel Gen7: Yes

------------------------------------------
Optional features:
Tiled Resources support:
NVIDIA Kepler: Yes (tier1)
NVIDIA Fermi: No (tier0)
AMD GCN: Yes (tier2)
AMD VLIW4/5: No (tier0)
Intel Gen7.5: no (tier0)
Intel Gen7: No (tier0)

Feature level support:
NVIDIA Kepler: 11_0
NVIDIA Fermi: 11_0
AMD GCN: 11_1
AMD VLIW4/5: 11_0
Intel Gen7.5: 11_1
Intel Gen7: 11_0

Conservative Depth Output:
NVIDIA Kepler: No
NVIDIA Fermi: No
AMD GCN: Yes
AMD VLIW4/5: Yes
Intel Gen7.5: No
Intel Gen7: No

Comparison of DX11/11.1 Support.  Source: http://forums.anandtech.com/showpost.php?p=35396249&postcount=14