AMD Mantle Performance Explored - An Introduction

AMD Mantle Explored with preliminary results

It has been a long time coming but we take a look at early and initial Mantle performance and a quick and rather basic initial article. The AMD Radeon 14.1 Beta driver has received many improvements, the one most awaited being Mantle ready. At the simplest level, Mantle is an Application Programming Interface (API), or a language that game developers can use to write code that creates the graphics on your screen. In its current iteration, the Mantle API uniquely leverages the hardware in the Graphics Core Next architecture (GCN) of modern AMD Radeon. The massive advantage of Mantle is that it will free up the processor, and thus faster processors get less important as you need lesser CPU cycles.
 

In this rather 'quickie' article (I merely had time for a few hours with Mantle) we'll be looking briefly at initial Mantle results both based on IGP measurements (the graphics processor inside an AMD Kaveri GPU (7850K). Then we'll mount also look at the same CPU but with a Radeon R9-290X mounted into the setup. Last but not least we'll also publish the very same measurements, but now based on a core i7 six-core setup. This way we can see if enthusiast class hardware (not CPU limited) will be affceted at all by mantle.

Battlefield 4 has been updated to support the Mantle API, the public beta release of the Catalyst 14.1 driver however is yet to be released, so only press has it at this time. This driver is very Beta I must add, Mantle responds slow switching in-between resolutions, but at the very least we didn't get any crashes. Testing will also be limited towards the IGP values and a single R9-290X for now. We’ll be using our standard BF4 benchmark run however since Mantle is designed to get rid of CPU limitation we'll look at BF4 with both Medium and Ultra Quality settings.

Testing Mantle is a bit different in the sense that DX11 is not supported, that means all overlay software can't detect DX11 and as such does not work. BF4 however has internal FPS counters and a recording mechanism allowing us to verify its average FPS. As stated, this is a quick overview of preliminairy results. We got the driver merely hours ago, and it is weekend so i like to wrap this up as fast as I can.
 

We use two setups with the  mentioned OS'es and Drivers:

1. Mainstream class - An AMD A10-7850K based setup with the usual gear like a SSD and 8GB of memory
2. Enthusiast class - An Intel Core i7 3960x Six core setup

So in BF4 (latest update) we can select eiither DX11 or Mantle now. If you are going to try it out yourself, after each change you must restart the the game.

• In the console type render.drawscreeninfo 1 to see if mantle  or DX 11 is active.
• In the console type PerfOverlay.drawfps 1 to get an active FPS counter.

Dice added a new tool to the in-game console to record frame times to a .csv file that can be analyzed & graphed in Excel or other similar tools. When the game is launched simply press the tilde “~” key to open console then use the command;

• PerfOverlay.FrameFileLogEnable 1 to start saving frame times
• PerfOverlay.FrameFileLogEnable 0 to stop.

The resulting .csv file will be located in your User/Documents/Battlefield 4 directory. The file will contain Frame Time, CPU Frame Time and GPU Frame Time in milliseconds. 

Above you are looking at a Kaveri's IGP, this is the A10-7850K internal graphics processor. Since Mantle is designed to clear CPU bottlenecks you won't see heaps of performance increases as the IGP obviously is very GPU bound. However, Medium quality settings are very playable. Let's call this a 10% performance increase.

Battlefield 4 on Kaveri with Mantle – Medium Quality Dedicated GPU

Now once we insert a dedicated graphics card things get interesting, in the setup above we installed a beastly Radeon R9-290X, these are the result based on the AMD A10-7850K based setup. Obviously we are massively CPU limited here with so much graphics horsepower waiting on the CPU. Again these are medium quality settings. On the next page we'll also have a peek at Ultra quality settings with  4xAA. But yeah these are massive perf gains.

Let's make it more interesting, next page please.