NOTE: Gamers with Mantle-enabled AMD Radeon™ graphics cards or AMD APUs must have AMD Catalyst™ 14.9.2 Beta (or newer) installed in their system. The game will allow users to select Mantle at runtime. This driver is available here.
Friends, diplomats, would-be bureaucrats, today is a truly exciting day in the history of PC gaming: we Sid Meier’s Civilization® addicts have an all-new Civ game to play! Before you commit to one more turn and push your bed time back by five hours, please join us in exploring the day-one Mantle support in Sid Meier’s Civilization®: Beyond Earth™.1
A GAME THAT SCARCELY NEEDS AN INTRODUCTION
Sid Meier's Civilization: Beyond Earth is a new science-fiction-themed entry into the award-winning Civilization series. Set in the future, global events have destabilized the world leading to a collapse of modern society, a new world order and an uncertain future for humanity. As the human race struggles to recover, the re-developed nations focus their resources on deep space travel to chart a new beginning for mankind.
As part of an expedition sent to find a home beyond Earth, you will write the next chapter for humanity as you lead your people into a new frontier and create a new civilization in space. Explore and colonize an alien planet, research new technologies, amass mighty armies, build incredible Wonders and shape the face of your new world. As you embark on your journey you must make critical decisions. From your choice of sponsor and the make-up of your colony, to the ultimate path you choose for your civilization, every decision opens up new possibilities.
AN AMD GAMING EVOLVED COLLABORATION
Firaxis Games and AMD have been in close collaboration on Sid Meier’s Civilization: Beyond Earth for many months, and indeed Firaxis has been an enthusiastic advocate and development partner for Mantle. Looking back at comments made by the studio in April, AMD Radeon™ customers definitely have cause for excitement:
By reducing the CPU cost of rendering, Mantle will result in higher frame rates on CPU-limited systems. As a result, players with high-end GPUs will have a much crisper and smoother experience than they had before, because their machines will no longer be held back by the CPU.On GPU-limited systems, performance may not improve, but there will still be a considerable drop in power consumption. This is particularly important given that many of these systems are laptops and tablets. The reduced CPU usage also means that background tasks are much less likely to interfere with the game’s performance, in all cases.
Finally, the smallness and simplicity of the Mantle driver means that it will not only be more efficient, but also more robust. Over time, we expect the bug rate for Mantle to be lower than D3D or OpenGL. In the long run, we expect Mantle to drive the design of future graphics APIs, and by investing in it now, we are helping to create an environment which is more favorable to us and to our customers.
These benefits should come as no surprise to gamers that have been following the history of Mantle, but they’ve been put to particularly good use in Civilization. Let’s dig in!
MANTLE IN SID MEIER’S CIVILIZATION: BEYOND EARTH
Mantle is a high-efficiency graphics interface (an “API”) that permits supporting software to leverage the complete capabilities of an AMD Radeon™ graphics card. Mantle does this by reducing software bottlenecks and widening the parallelization of a game’s renderer.
Akin to allowing more cars on the road with no additional congestion, Mantle’s design endows a PC with the power to process more simultaneous information. New rendering techniques, higher framerates, more fluid gameplay and superior visual fidelity are all possible with Mantle. AMD is over a year ahead of other graphics companies in delivering this kind of technology to its customers and development partners.
John Kloetzli, Firaxis Games’ Principal Graphics Programmer for Civilization: Beyond Earth, put it this way:
“If you play [Civilization: Beyond Earth] for 40 hours, you’ve built an enormous empire. There’s a huge amount going on, besides just these tactical battles. We do allow you to zoom out quite far. […] When you back up, you see your whole empire at once. That’s demanding. That’s when the performance, typically, in PC strategy games begins to go down. This is exactly the situation wherein we’re incredibly excited about Mantle.”
We also asked John if Mantle was difficult or complicated to implement:
“There definitely is cost involved [for supporting Mantle]. It’s definitely not an API that’s going to hold your hand and it’s not for hobbyists, really. But Mantle is not a significant overhead for a professional graphics team to add to a game. In fact, I did most of the design and programming of the graphics features in [Civilization: Beyond Earth] myself, and I also found time to do the vast majority of the programming for our Mantle backend as well. We fit it in our production schedule, it didn’t push us back any, and we’ll release [Mantle] concurrently with the DirectX® 11 version.”
That sounds like a winning combination for gamers and developers. Let’s see how Firaxis put Mantle to use!
MANTLE SPLIT-FRAME RENDERING WITH AMD CROSSFIRE™ TECHNOLOGY
UPDATE: Firaxis Games has published additional commentary on split frame-frame rendering (SFR) in Mantle. You should give it a read!
With a traditional graphics API, multi-GPU arrays like AMD CrossFire™ are typically utilized with a rendering method called “alternate-frame rendering” (AFR). AFR renders odd frames on the first GPU, and even frames on the second GPU. Parallelizing a game’s workload across two GPUs working in tandem has obvious performance benefits.
As AFR requires frames to be rendered in advance, this approach can occasionally suffer from some issues:
- Large queue depths can reduce the responsiveness of the user’s mouse input
- The game’s design might not accommodate a queue sufficient for good mGPU scaling
- Predicted frames in the queue may not be useful to the current state of the user’s movement or camera
Thankfully, AFR is not the only approach to multi-GPU. Mantle empowers game developers with full control of a multi-GPU array and the ability to create or implement unique mGPU solutions that fit the needs of the game engine.
In Civilization: Beyond Earth, Firaxis designed a “split-frame rendering” (SFR) subsystem. SFR divides each frame of a scene into proportional sections, and assigns a rendering slice to each GPU in AMD CrossFire™ configuration.2 The “master” GPU quickly receives the work of each GPU and composites the final scene for the user to see on his or her monitor.
ESSENTIAL READING: How does split frame rendering work in Civilization: Beyond Earth?
As you can probably surmise, SFR requires high parallelization, efficient inter-GPU communication, and reliable delivery of slices to the master GPU. AMD Radeon™ graphics cards running Mantle are uniquely equipped to meet those requirements.
NOTE: Sid Meier’s Civilization®: Beyond Earth™ presently supports a maximum of two graphics cards. To try mGPU on Mantle for yourself, navigate to %homepath%\Documents\my games\Sid Meier's Civilization Beyond Earth\ in "My Computer." Open the GraphicsSettings.ini file and set "Enable MGPU=1".
MANTLE MULTI-THREADED COMMAND BUFFER SUBMISSION
As Mantle rises to meet the parallelization requirements of SFR, Mantle also supercharges Beyond Earth’s ability to utilize a gamer’s multi-core CPU.
In computer graphics, a “command buffer” is a type of memory buffer containing instructions (or “commands”) that the GPU will execute to carry out required rendering workloads. Feeding the GPU with a continuous, uninterrupted flow of commands is essential to keeping the whole graphics card at high utilization. High utilization can yield higher framerates and/or higher image quality, depending on the focus of the game developer.
Mantle is remarkable in its ability to spread a game engine’s command buffer submissions across multiple CPU cores, ultimately allowing for a wider stream of graphics work to be processed and queued to the GPU.
In the case of Sid Meier’s Civilization: Beyond Earth, you’ll see later in this blog that this wide communication lane to the AMD Radeon™ GPU is used to sustain higher overall framerates when empires get large and detailed in the late game.
EQAA in Mantle
Aliasing, the nasty “jaggies” on the edges of 3D objects in a PC game, is the bane of gamers everywhere. Aliasing is produced when a sharp edge is rendered to a monitor, which doesn’t offer sufficiently high pixels per square inch to properly express a smooth line.
There are many types of anti-aliasing designed to combat this unwanted phenomenon, and the majority of them fall into a category known as “multisample anti-aliasing” or MSAA. As the name implies, MSAA relies on “samples,” which is a graphics card’s test for whether or not a pixel on your monitor is occupied by one or more objects from the game world. If a pixel is covered by more than one triangle then the final contents/color of that pixel will be a blend of the information covering that pixel to produce a smoother edge.
Games and GPUs can cooperate to increase the number of samples being taken with each pixel, and these samples may test for color or coverage. Higher coverage sampling improves the accuracy of detecting whether or not an object occupies the pixel; higher color sampling improves the blending between samples confirmed to be occupied. Gamers increase the sample rate by choosing 2x, 4x or 8x MSAA, causing every pixel to be tested for color and coverage in two, four or eight locations.
LEARN MORE: A Quick Overview of MSAA
Like MSAA, AMD’s Enhanced Quality Anti-Aliasing (EQAA) also comes in 2x, 4x and 8x sampling modes, but each EQAA mode takes twice as many coverage samples as MSAA. Increased coverage testing allows the GPU to more accurately detect objects within a pixel, potentially allowing EQAA to detect and smooth a hard edge that might have been missed with fewer samples. Coverage samples are computationally cheaper than color samples, so EQAA proves to be a good compromise between quality and performance.
Civilization: Beyond Earth automatically enables EQAA in Mantle (and DirectX®!) on supporting AMD Radeon™ GPUs when the user chooses to enable the in-game anti-aliasing options.
Customers with older GPUs that lack hardware support for Mantle can still take advantage of EQAA through the AMD Catalyst™ graphics driver. Simply enable 2x, 4x or 8xMSAA in the options menu of your favorite game (if supported), and ensure you have “enhance application settings” selected in the 3D Application Settings tab of AMD Catalyst™ Control Center.
Throughout this blog you’ve learned how Mantle can be used to enable great multi-GPU responsiveness, superior CPU multi-threading and smooth anti-aliasing. But thousands of customers effectively tell us every day that single-GPU performance matters more than anything – by owning single-GPU systems!
Our collaboration with Firaxis Games to integrate Mantle with Civilization: Beyond Earth is a landmark technical achievement that proves we’re listening. Across every GPU comparison we tested, AMD Radeon™ graphics cards with Mantle delivered the best performance. In fact, the AMD Radeon™ R9 290X 8GB is the fastest graphics single-GPU card on the planet. If you want to play Civilization: Beyond Earth, It doesn’t get any simpler than that.3
AMD and Firaxis Games have worked together for months, not only to equip Civilization: Beyond Earth with a Mantle-based renderer, but to refine the Mantle specification with the features that Firaxis wanted to see. Hundreds of collaborative man hours are coming together for AMD Radeon™ customers at this very moment, and the results speak for themselves: fast, beautiful, efficient performance for Sid Meier’s Civilization: Beyond Earth.
That is the power of the AMD Gaming Evolved Program. We hope you enjoy one more turn!
Sid Meier's Civilization: Beyond Earth is a technology partner in the AMD Gaming Evolved program. Robert Hallock does Technical Communications for Desktop Graphics at AMD. His postings are his own opinions and may not represent AMD’s positions, strategies or opinions. Links to third party sites, and references to third party trademarks, are provided for convenience and illustrative purposes only. Unless explicitly stated, AMD is not responsible for the contents of such links, and no third party endorsement of AMD or any of its products is implied.
- Mantle application support is required.
- AMD CrossFire™ technology requires an AMD CrossFire Ready motherboard and may require a specialized power supply and AMD CrossFire Bridge Interconnect. Check with your component or system manufacturer for specific model capabilities.
- In Sid Meier’s Civilization®: Beyond Earth™ internal benchmark test at 3840x2160, the AMD Radeon™ R9 290X 8GB with Mantle outperforms the GeForce GTX 980 with DirectX® 11, NVIDIA’s highest-performing single-GPU graphics card as of October 20, 2014, by 45.38 average FPS to 44.89 average FPS using the Ultra in-game preset with 8xAA. Test system: Intel Core i7-4960X, 16GB DDR3-1866, Asus SABERTOOTH X79, Windows 8.1 x64, AMD Catalyst™ 14.9.2 Beta and ForceWare 344.16 WHQL.