DirectX 12 IHV Support Explained: Maxwell's Feature Level 12_1, GCN's Resource Binding Tier 3 and Intel's ROV at FL 11_1

The DirectX 12 standard and its specification are both tricky things to fully understand at the best of times, only with companies throwing around things like "full DirectX 12" support - it gets even more complicated. Nvidia has been marketing the GM200 as the first GPU with total DirectX 12 support, while AMD has been offering Resource Binding at Tier level 3. Intel has remained mostly silent on the subject simply their GPUs have featured Raster Order Views at Characteristic Level 11_1 for a long fourth dimension. So who exactly has the mythical maximum possible DirectX 12 support down to the last digit? The correct, technical answer is: no one.

There are very interesting times, and the arrival of DX12 opens a new affiliate in GPU tech.

Does Nvidia'south feature level 12_1 trump AMD's resource binding tier 3 and async shaders?

Before we get into the nitty gritty details, lets differentiate between APIs, Feature levels and HW specifications such as Resource Bounden. DirectX 12.1 is an API or an Awarding Programming Interface. Information technology is simply put, code that forms a bridge between the GPU and whatever stop user software. Anybody is thoroughly excited nigh the DirectX 12 API - because its low level capabilities are a huge upgrade over its predecessor. Low level access, as almost of our readers know, ways the ability of the API in question to access parts of the GPU straight. Now, we come to feature_levels. Feature levels are pre defined standards of GPU hardware capabilities and take nigh nothing to do with the API in the very strict sense. The DirectX 12 API requires graphics hardware with support for Feature Level 11_0 at the very to the lowest degree to run (divers below). But even later on a new Feature Level is divers, many old GPUs and graphics architectures can still qualify for that characteristic level. For example a previously Characteristic Level 11_1 graphics menu may very well meet all the requirements to fully support Feature Level 12_0.

A feature level will withal, usually require a similarly named API to access its features in their entirety. . So basically, all GPUs with FL 11_0 to 12_1 support can run DirectX 12 API completely and fully. The much hyped about reward that is the reduction of CPU overhead - anybody volition get that (provided you fall in the FL 11_0 to 12_1 band). The thing is nonetheless, these new GPU had new hardware features, something that just the DirectX 12 API can finally admission: and so new standards had to exist created: namely FL 12_0 and 12_1. Before nosotros become any farther, given below is a curt summary of the requirements for feature level qualification:

• FL 11_0: Supports Resource Binding Tier ane and Tiled Resources Tier one

• FL 12_0: Supports Resource Binding Tier 2, Tiled Resource Tier 2 and Typed UAV Tier one

• FL 12_1: Bourgeois Rasterization Tier 1 and Raster Order Views (ROV)

Now that nosotros know what the definitions are, here is the complete specification table of all IHVs with released hardware (including the latest Skylake iGPU and GM200):

IHV Hardware Specification Comparing

WCCFTech	Intel			AMD		Nvidia
Architecture	Haswell	Broadwell	Skylake	GCN ane.0	GCN i.1	Fermi	Kepler	Maxwell i.0	Maxwell ii.0
Resource Binding	ane	1	2	3	3	one	2	two	2
Bourgeois Rasterization	0	0	0	0	0	0	0	0	ii
Tiled Resource	1	ane	2	i	two	1	two	two	3
Raster Order Views	Yes	Aye	Aye	No	No	No	No	No	Yep
Typed UAV Formats	0	0	ane	1	ii	0	0	1	1
Characteristic Level Specification	11_1	11_1	12_0	11_1	12_0	11_0 + Partial 11_1 support	11_0 + Partial 11_1 support	12_0	12_1

Then hither is the thing. Maxwell 2.0 (GM200) has the hardware characteristics necessary to get the 12_1 postage stamp, so it does. Notwithstanding, AMD's GCN really has Resource Binding Tier 3 for a very long time now, not to mention Typed UAV Format Tier ii and Asynchronous shaders for parallel functions. Similarly, Intel has supported Raster Gild Views since Haswell iGPUs and has been rocking it on Characteristic Level 11_1. To put this into perspective Nvidia'southward architectures supports ROV but after the GM200 Maxwell. Y'all can clearly see that no hardware vendor has the undisputed best GPU hardware specification around. Every IHV has a weakness or missing specification in some form or the other. So who exactly has the all-time relative specification all things considered? This is where information technology gets really tricky and also unanswerable, mostly unanswerable.

So which IHV specification is better?

The question we can however reply is: which specification (or lack thereof) will actually translate to an increased (or decreased) gaming experience at the end of the solar day? Here, the answer is relatively simpler to explain. Lets kickoff with AMD's border. Resource Binding is basically, the process of linking resources (such every bit textures, vertex buffers, index buffers) to the graphics pipeline and so that the shaders tin process the resource. This ways that AMD'southward architecture is mostly limited merely by retentivity and while this is a desirable trait, information technology is something that will happen out of sight, without translating to anything a gamer tin observe on-screen. Similarly Typed UAV formats isn't something an end user can observe. Currently at that place isn't a fully adult ecosystem for these and just when VR becomes mainstream volition these affect annihilation only a very small minority. Asynchronous compute shaders however, is a performance enhancing feature so the benefit is not strictly based on new visual furnishings merely on improved performance.

I am not going to get into detail most Intel primarily because its non actually a competitor to Nvidia or AMD. Information technology has supported Raster Guild Views since the Haswell days (fulfilling 1 half of the requirement for 12_1) and now with Skylake information technology also boasts full DirectX 12 API support with the Characteristic Level 12_0.

Finally, nosotros come to Nvidia. Nvidia has something that no other IHV currently has: and that is Conservative Rasterization. While the qualifying requirement is only Tier 1, GM200 has Tier ii Bourgeois Rasterization support. Here is the matter however, Conservative Rasterization is a technique that samples pixels on screen based on the primitive in question and is much more authentic than conventional rasterization - in other words, it volition make a difference to the end user in the form of special graphical effects. Bourgeois Raster itself will give way to many interesting graphical techniques - Hybrid Ray Traced Shadows for i. We can conclude therefore that Nvidia's relative border is something that volition actually touch on the average gamer's experience.

An instance of conservative raster based furnishings in the form of Nvidia'due south Mech Ti feature demo is embedded beneath:

TL;DR: So summarizing, all IHVs fully and completely support the DirectX 12 API. No hardware vendor can claim 100% support of all specifications and the differences are usually negligible in nature. That said, if one is deciding by features observable by the end user and gaming experience, the slight advantage and edge goes to Nvidia with its Feature Level 12_1 support. Keep in heed however, that developers usually lawmaking for the lowest common denominator, which ways Nvidia'south border depends entirely on how many devs use it.

Source: https://wccftech.com/directx-12-support-explained-maxwells-feature-level-12-1-gcns-resource-binding-tier-3-intels-rov/

Posted by: smithbutwousuble.blogspot.com

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