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Image Quality Comparison And Wrap-Up

AMD Mantle: A Graphics API Tested In Depth
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Image Quality Comparison: Mantle vs. DirectX

When the Mantle patch first launched, we saw evidence of inconsistent visual output using the newer API compared to DirectX 11 in Battlefield 4. So, I took some screenshots in the two games we tested for a comparison. Here are the results:

Previously, it was reported that there was a difference in saturation and contrast between Mantle and DirectX in Battlefield 4. But at this point in development, the disparity is apparently gone. We know DICE addressed the bug publicly and claimed to have fixed it in a subsequent patch.

As for Thief, I didn't find any meaningful image quality disparities between Mantle and DirectX.

How does Mantle impact the future of gaming?

Today we thoroughly tested the only two benchmarkable titles with AMD Mantle support. Thief exhibits clear (and impressive) performance gains under the API and really does mitigate much of the platform-oriented bottleneck imposed by low-cost CPUs. Battlefield 4 demonstrates gains with a Radeon R9 290X, while mid-range and low-end discrete cards suffer from what AMD suggests is a memory-related issue under Mantle. I tested a Radeon R9 270X with 4 GB as verification, and while Mantle didn't hurt performance, it also didn't enjoy an advantage. AMD says Mantle is in its beta stage, and so perhaps anomalies like this are expected as we sort through corner cases.

Regardless, based on most of our tests (and developer testimony), it's pretty clear that Mantle offers certain advantages over DirectX 11, at least. We don't have any OpenGL-based games to compare, but the claim is that both entrenched graphics APIs are limited compared to Mantle. So, what does that mean for you as a PC user?

In the short to medium term, Mantle may provide owners of GCN-based Radeon cards a performance boost in a very short list of games. That speed-up will be minimal on platforms with fast host processors like Intel's Core i7. But it should be more significant on lower-end CPUs like the FX-4170, A10 APU, or Athlon X4.

The list of Mantle-capable games will grow in the months to come. But even if you go by AMD's count, the total isn't large. Developers who find DirectX 11 too constraining for their engine may find it worthwhile to invest in a Mantle code path. Of course, that's extra work necessitating additional resources. In this way, Mantle is currently an equivalent to Nvidia's PhysX: a vendor-specific benefit in a small number of titles.

Step out further. Once AMD introduces its Mantle SDK, it's theoretically possible for Intel and Nvidia to develop a Mantle-compatible driver, which would probably give the ISV community more impetus to jump on the bandwagon. Frankly, this is unlikely. It doesn't make a lot of sense to hitch your cart to a horse driven by a competitor. Intel has reportedly asked for access to the Mantle SDK, but this is probably for internal testing purposes.

That brings us to the long game, which is where AMD's collective head has to be right now. Will there be a place for Mantle once DirectX 12 arrives, with its own take on minimalism and the ability to execute fully parallel draw submissions concurrently on multiple CPU cores? It seems pretty clear that Intel and Nvidia will embrace the Microsoft option. I suppose that if Mantle is closely compatible with DirectX 12, developers might be willing to invest some development time to support it. But AMD will inevitably support DirectX 12 too, so the work could be redundant. Once DirectX begins propagating, Mantle's biggest strength will be its ability to expose any new Radeon-exclusive features quickly for developers who want to access them, a la 3dfx's Glide.

Of course, the discussion emphasizes PCs, but consoles are in play here as well. If Microsoft and Sony were to embrace Mantle on their AMD-based platforms with lightweight Jaguar-based x86 cores, the API would almost necessarily enjoy a leap in developer support. Much of the PC game library is ported from (or at least developed concurrently with) console builds. Microsoft naturally has the incentive to wait until DirectX 12 is ready. As for Sony, the PlayStation 4 has its own API, which is advanced compared to DirectX 11 and OpenGL. Johan Andersson, DICE's lead graphics programmer, has said that the “PS4 graphics API is good as well; we don’t need Mantle on PS4.”

Really, the unknown quantity could be Valve's Steambox. While AMD currently doesn't support Mantle in its Linux driver, the company hinted it might be possible in the future. Assuming Valve can figure out how to make its concept hold some value (right now, we have a hard time seeing it), there may be demand for Mantle there. SteamOS has a long way to go before this is a significant factor, though.

In the meantime, Mantle does represent innovation. Even if it's eclipsed by DirectX 12, there's every reason to believe that Mantle is what spurred Microsoft into motion on its next-gen graphics API. Clearly, there was a real need or desire to eradicate overhead affecting the gaming experience. And whether AMD compelled action or the development was concurrent, AMD got its message out first. For now, and until AMD makes more notable overtures to the industry, we're looking at it as a value-added feature like PhysX. We don't mean this in a technical sense, obviously, but in the sense that it provides an advantage to one graphics card manufacturer in a handful of games.

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Top Comments
  • 10 Hide
    Memnarchon , July 16, 2014 1:07 AM
    Mantle is not glide. 3DFX had 85% of the GPU share when they had glide so it was easier for developers to use the glide (AMD has 35% right now).
    But Mantle did something really good for gamers. Till now Microsoft with no competition didn't gave too much attention in performance optimising the DirectX. They gave Microsoft a reason to improve DirectX (so they will bring DX12) in the way mantle works. This benefits all the gamers.
    Unfortunately I have a feeling that Microsoft will give DirectX12 only with Windows9 (due to kernel limitations at their pockets).
    If this will be true then Mantle might have more life than most users expected to (since it wil take time for windows 9 to rule the market share)...
Other Comments
  • 0 Hide
    Amdlova , July 16, 2014 12:44 AM
    memory problems... so my 260x with 1gb will sufferrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
  • 10 Hide
    Memnarchon , July 16, 2014 1:07 AM
    Mantle is not glide. 3DFX had 85% of the GPU share when they had glide so it was easier for developers to use the glide (AMD has 35% right now).
    But Mantle did something really good for gamers. Till now Microsoft with no competition didn't gave too much attention in performance optimising the DirectX. They gave Microsoft a reason to improve DirectX (so they will bring DX12) in the way mantle works. This benefits all the gamers.
    Unfortunately I have a feeling that Microsoft will give DirectX12 only with Windows9 (due to kernel limitations at their pockets).
    If this will be true then Mantle might have more life than most users expected to (since it wil take time for windows 9 to rule the market share)...
  • -3 Hide
    ZolaIII , July 16, 2014 1:07 AM
    Next Open GL specification is almost redy & will be announced next month in (ironically) Vancouver Canada. Naturally it will be available on all platforms (that want to integrate OGL) & it will be addressing lover overheads. As gaming market is getting more fragmented it's getting natural to develop for api that can run on all platforms.
  • 9 Hide
    tomfreak , July 16, 2014 2:18 AM
    Is the battlefield 4 tested in multi-player?

    [Answer By Cleeve:]

    It was tested in single player, as its easier to get consistent results. We're trying to eliminate variables except the graphics engine as much as possible.
  • -3 Hide
    chaosmassive , July 16, 2014 2:51 AM
    "AMD Mantle: AMD's PhysX "

    please do a research what is Mantle before post
    it seems you don't understand what are you writing about.

    [Answer by Cleeve:]

    I think the problem may be that you don't understand the context of the answer, which does not equate Mantle with PhysX on a technical level.

    We equate Mantle with PhysX in the sense that it's a value-add that assists in a limited number of games. Its not a universal advantage.
  • 0 Hide
    ta152h , July 16, 2014 4:47 AM
    As a programmer of 30 years, that's arguably the worst description of an API I have heard.

    An API is a set of commands, with required parameters, a software package presents to another application that wishes to use its services. It's essentially the language to use the services it provides.

    Mantle isn't just an API. It's an abstraction layer that makes it unnecessary for the developer to write directly to the hardware, which is tedious, time-consuming and extremely difficult to do on a large product. The API is what Mantle accepts to tell it what to do, and what the programmer must learn to use it, but it is NOT all Mantle is. It's just how to talk to it.

    A pure API would be something someone demented would write, because it would mean you could issue commands to do nothing. I'm guessing Apple is patenting this technology now.

    [Answer by Cleeve]

    I'm sorry you feel that way. I don't agree as I feel it's a useful high-level primer for folks who haven't been programming for 30 years, but you're certainly entitled to your opinion. :) 
  • -4 Hide
    elbert , July 16, 2014 4:54 AM
    On page 4 its clear mantle doesn't work well with Intel's Hyper-Threading but what about Intel's 6 core CPU's? Does mantle give an Intel 6 core a bigger advantage in games that dx? I wouldn't throw mantle under the bus just due to its unoptimized for Hyper-Threading. Please add an Intel's 6 core to these tests.
  • 0 Hide
    SteelCity1981 , July 16, 2014 5:55 AM
    I can see intel supporting mantle in its future gpu hardware. I mean just recently intel asked amd for its mantles api specs. So intel using mantle in the future is much more plausible then Nvidia using mantle.
  • 2 Hide
    K-beam , July 16, 2014 6:55 AM
    Mantle can actually become quite relevant in any next-gen ultra-portable x86 APUs that AMD come up with. Especially useful if coupled with proper integration with Steam-OS.
  • 6 Hide
    cypeq , July 16, 2014 7:07 AM
    How I see line graph with 15 positions.



    (Image viewable on Forum here:) 
    http://www.tomshardware.com/forum/id-2221312/amd-mantle-graphics-api-tested-depth.html#13731289
  • 1 Hide
    serendipiti , July 16, 2014 7:10 AM
    Nice analysis.

    Probably there wasn't a DirectX 12 on the works because of maturity (what else add to DirectX that it pays for?) and Mantle showed the way.

    I don't like the comparation to PhysX (because of what has finally become) and the fact that Mantle won´t bring new features to games.

    It is Mantle here to stay, probably, sadly, not. Its success as an universal graphics API is complicated:
    if it was on time for PS4, XBox One (M$...) and Linux / Valve Steam OS and above all: Mobile devices (ARM...), if it could get NVidia involved also, perhaps Mantle would gain enough momentum to become an accepted universal standard.

    The other battle field is on the developer front: get major 3D Engines to support a Mantle code path (and what are the costs related to maintaining that code path from a developer standpoint).

    ta512, as deep as a naming convention discussion can go, what AMD is doing is an API which implements a Hardware Abstraction Layer for the graphics cards of any hardware vendor (AMD, NVidia, Intel). What have tested here is the AMD own implementation of that API made to run on AMD hardware.

    What is open source is the API, not the AMD own implementation.

    This Is like discussing if ARM it is a processor or an instruction set... and what / where the difference is.

    In a case scenario where you have BattleField 4 running on an i7 with an NVidia card with a Mantle enabled driver (let's suppose Nvidia gets on the Mantle train) the only thing AMD would have done would be decide how the game will talk to the graphics card, but neither the game, the driver, the graphics card, none of these would be AMD's work,,,

    Cheers
  • 4 Hide
    cleeve , July 16, 2014 7:12 AM
    Quote:
    How I see line graph with 15 positions.


    Urmehghurd, I LOLed. Nice one.

    Yeah, this is a little ugly. Note that I made the mantle results thicker so it'd be slightly easier to pick out the Mantle trends, but yeah. Would be a little easier to pinpoint specific cards with less data.
  • 0 Hide
    guskline , July 16, 2014 7:19 AM
    Very interesting article. I have a Sapphire R9 290 Tri-X in my FX8350 rig and BF4 has slightly faster fps in Mantle than in DirectX
  • 3 Hide
    Alethinos , July 16, 2014 7:21 AM
    Is it just me, or is that last Frame Time Variance graph on the 8th page labeled wrong? I wouldn't think frame time variance would be displayed in frames per second, and if it was, the majority of the items on the chart would (hopefully) not be between 0-10 if "higher is better".

    Maybe I misunderstand what the chart is trying to show.

    [Answer by Cleeve:]

    Doh! You're quite right, I'll get that fixed.
  • 1 Hide
    ddpruitt , July 16, 2014 7:25 AM
    I think Tom's doesn't really understand the difference between the OS API and a regular API. The entire first page muddies the discussion. Mantle isn't an API it's the low level driver behind the API, and that can be made as lean or as bloated as possible with no changes to the API itself. As an example Android uses the Java API but it's a completely different implementation than what you would see on an EA game.

    I'm also concerned that Battlefield was used as a benchmark. Although I understand that the available benches are limited by those that support Mantle Battlefield is notoriously difficult to get consistent results with, I would consider the differences well within experimental error and therefore unreliable.
  • 3 Hide
    Onus , July 16, 2014 7:30 AM
    Quote:
    Alright, I think I have a handle on the basics of Mantle. What now?

    For the sake of professional image, please remember that Alright is Alwrong. All right?
    [/nazi]
    To the meat of the article, it does look like Mantle will help some of AMD's weaker CPUs some of the time, but if that isn't what you have, Mantle does not make a large enough difference to influence buying decisions (sort of like PhysX; in only a few cases does it really matter). If your system is one of those cases, it is a pretty substantial difference, but for many people it won't be.

  • 1 Hide
    cleeve , July 16, 2014 7:34 AM
    Quote:
    I think Tom's doesn't really understand the difference between the OS API and a regular API. The entire first page muddies the discussion. Mantle isn't an API it's the low level driver behind the API


    I'm not sure I read you here. There's a Mantle API and a Mantle driver, these are separate entities.

    I've been at briefings and talked to developers, and it's been made very clear that Mantle is a graphics API, which requires a Mantle-compatible driver to work with specific hardware.

    Quote:
    I'm also concerned that Battlefield was used as a benchmark. Although I understand that the available benches are limited by those that support Mantle Battlefield is notoriously difficult to get consistent results with, I would consider the differences well within experimental error and therefore unreliable.


    I'll have to disagree on this one. We have a BF4 test run that has been extremely reliable and repeatable for us, usually with less than 1.5 FPS difference in three runs.

    When there's an issue found in data, it's easy to assume its the test. Sometimes it's what you're testing, though. We can't ignore issues out of convenience.

  • 3 Hide
    Yuka , July 16, 2014 7:53 AM
    You guys need to test MP... I know its hard and blah blah, but you can just add error margin to results and just describe the differences if you guys notice any.

    You guys are testing a grippy car in just a drag race. That's unfair. You need to add cornering as well.

    Cheers!
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