Also...how to use it:
How to make Mantle work in BF4
Now let's go over what is required to make Mantle work in BF4.
AMD has a FAQ if you are encountering any issues.
Please read this blog post from DICE which will provide all the info about the Mantle patch in BF4: Mantle renderer now available in Battlefield 4.
The very first requirement is that you have the proper GPU. You need a Graphics Core Next GPU (GCN.) A Graphics Core Next-based GPU, such as one from the AMD Radeon R9, R7, HD 7000 or HD 8000 Series GPUs.
Next open up Origin and let it update BF4 to the latest patch. However, once that is done, you still won't be able to enable Mantle until the proper driver is installed.
The current supported driver to make Mantle work is Catalyst 14.1 Beta 1.6. Note this is a Beta driver, and there are issues. Note the Known Issues list at the middle of that webpage. Please, properly uninstall your previous driver first. In fact, you should run a driver cleaner program to clear out all registry files and INF cache stores of old driver pieces. This is very important. There is a free utility called DDU which will do so. Info about DDU, and a link to its download location.
Once you have this done, then you need to manually enable Mantle from within the game's graphics option. At the top of the graphics menu is a new selection called "Graphics API" the default is Direct3D, change it to Mantle. Quit the game, and restart the game. You will now be running in Mantle.
One thing you will discover is that FRAPS does not work when the AMD Mantle API is active. This is a completely different API from Direct3D, so FRAPS doesn't know what that is. Thankfully DICE has introduced a Frame Time capture tool into the game. From this, we can manually calculate the Average FPS from a run. We won't be able to show you Frame Rate over time currently. All we are able to show you is the Average FPS, and the Frame Times.
When the game is launched simply press the tilde "~" key to open console then use the following 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. To calculate average fps for the run you divide the total number of frame entries in the log (which is total number of frames for the session) over the total amount of time.
Average FPS = (Total # of Frame Time Entries) ÷ (Σ (Total # of Frame Times in ms) ÷ 1000)
Another in-game command that is useful to use is "Render.DrawScreenInfo 1" that will now show additional on-screen information about your CPU & GPU config, resolution and as well as if Mantle or DirectX 11 is used for rendering.