Mantle vs DirectX 11

Unlike consoles, PC's are machines with alot of "whims", where a single element can make the difference between a game running at 60 frames per second or 30. As such, the announcement of Mantle technology in September, and all the promises that came from AMD, generated a lot of interest among PC gamers.

Mantle is an API (application programming interface) created by AMD to compete with DirectX. A major advantage of this API is it gives developers a level of more direct communication with the graphics card, removing some of the CPU processing. As such, improvements will be more noticeable on computers that are limited by the processing unit and not the graphics card. Top of the range computers that do not have major limitations in any of these fields, will see smaller benefits from Mantle.

Despite the announcement in September, you can already take advantage of Mantle. The first drivers (Catalyst 14.1) are now available in beta format and some games/programs already support it, including Star Swarm and Battlefield 4 technology. However, it is evident that it still needs a lot of work. For now, only users with graphics cards based on the Graphics Core Next (HD 7xxx and Rx) processor can take advantage of Mantle and there are problems with various types of settings. Still, we can already see how far this technology offers improvements for players when compared to DirectX .

Star Swarm

The Star Swarm (available on Steam) is a free application designed to show the potential of Nitrous, the graphics engine developed by Oxide Games. It is also one of the few ways that users have to test the advantages of the Mantle compared to DirectX. Unlike Benchmark applications like PCMark or 3DMark, Star Swarm presentes real time computing, which can cause results changes. To ensure fair results, we ran three 360 seconds tests on Mantle and three in DirectX, in two distinct modes - a total 12 tests. We calculated and compared the average fps in each of the two options - Follow and RTS - and chose the graphics option "Extreme" with a resolution of 1920x1080 .

In the first scenario, Follow, Mantle increased performance by 60.48% over DirectX. This reflected an increase of 15 FPS, going from 24.80 to 39.79 in DirectX using AMD's new technology. During testing in RTS - a more distant vision camera that aims to show the capabilities of Nitrous in any strategy games and puts thousands of units on the screen simultaneously - the increase was even more substantial. From the average 6.72 FPS achieved in DirectX, we went to an average of 24.80 frames per second on Mantle, an increase of 258.81%.

Since the Mantle is an API - intended to improve communication between the game, the CPU and GPU - the results will most certainly vary. More powerful systems, capable of dealing with the power source of the Nitrous, may see less relevant improvements, while weaker systems should be treated to a higher percentage increase.

Battlefield 4

Electronic Arts immediately stated their support to Mantle during AMD's announcment in 2013, revealing that Battlefield 4 would support the API. Unlike Star Swam, BF4 does not give us a linear benchmark tool to do the job for us. However, it was possible us to record the CPU and the GPU performances during playtime.

To validate the improvements in the Single Player mode, we opted for the 3rd campaign level - South China Sea - a 1920x1080 resolution and graphical settings on Ultra. It may not be the most demanding map on the game, but it offers a good variety of action and scenarios. From the beginning inside the USS Valkyrie, to the trip to the ship Titan (open field with a number of physical effects and water), through to fighting in enclosed areas filled with smoke and fire, and naval battles with various aerial vehicles patrolling the area.

The performance increase was not as significant as in Star Swarm. The average FPS went from 54.89 in DirectX11 to 65.70 in Mantle: an increase of 19.69%. However, the use of the AMD's API offered a lot of stability, especially at the level of the CPU, something DirectX clearly failed. With DirectX, our processor had a much larger amount of "spikes". The percentage increase may not be significant, but the improvements of communication between the CPU and GPU were clear, and the result was a more fluid experience .

One of the biggest surprises we had with Battlefield 4 was during multiplayer. Tests in Siege of Shanghai, with 64 players, showed improvements in Mantle but, surprisingly, were not as high as expected. In DirectX we reached an average of 63.69 FPS. This value increased to 70.54 in Mantle: a difference of only 10.76%. The caveat is that these tests were done in real situations, with 64 real players. That is, an environment that can not be fully replicated for purposes of benchmarking, where results could easily be higher or lower. Our idea was only to test the technology, and to see if it works, not to define where it is best optimised or in which conditions it does best, and as such we feel that these numbers are interesting enough for the average gamer.

Conclusion

The fact that the drivers are still in beta means there are still many steps to be taken with regards to Mantle. Improvements could well prove larger depending on the player's own machine, but from what we've experienced, the technology clearly works. The communication between the processor and graphics card is more effective, resulting in a more fluid gaming experience with fewer breaks. However, without a mass adoption among producers of video games, and an expansion of support for more graphics cards (thus covering a wider range of users), it can't really hope to impact the supremacy of DirectX. The current lack of support for Linux systems can also prove a counter point if the SteamOS (and eventually Steam Machines) succeeds.

EA promised that all upcoming games to use Frostbite 3 engine will be optimised for Mantle. The next game planned to take advantage of the technology is Thief, which will hit stores in late February, and Plants vs. Zombies: Garden Warfare. In the 90s something similar had been attempted with deployment of technology in 3dfx Glide graphics cards. This API eventually died with the evolution of DirectX. It remains to be seen whether this is a case of history repeating or rewriting itself.

Test System
CPU: AMD MHz [email protected]
RAM: Corsair Vengeance 8GB DDR3 1600MHZ
GPU: HIS 7950 IceQ BOOST 3GB DDR5
Drive: Drive: 250GB Samsung 840 EVO
Operating System: Windows 8.1
Drivers: Catalyst 14.1 beta drivers