While there were some reports flying around about further delays of the Battlefield 4 Mantle patch it has been delivered on time today by DICE. The necessary AMD Catalyst 14.1 beta drivers - to get Mantle optimisations to work - are yet to be released publically but are expected to be available later today.
Johan Andersson, one of the Technical Directors in the Frostbite team, said about the update: "Battlefield 4 on PC is already quite heavily optimized using DirectX 11 and DirectX 11.1, but with Mantle we are able to go even further: we’ve significantly reduced CPU cost in our rendering, efficiently parallelized it over multiple CPU cores and reduced overhead in many areas." Andersson added that the best performance gains are observed when a game is bottlenecked by the CPU "which can be quite common even on high-end machines".
How to use Mantle in Battlefield 4
First of all you'll have to download the Mantle update patch for Battlefield via your Origin PC client. The download is 1.23GB. Then you will need to get the AMD Catalyst 14.1 Beta drivers when they are released. Please note that only the following GCN cards will work for now: AMD Radeon R9 290X, R9 290, R7 260X and Kaveri APU. Also you need Windows 7 or 8.X 64-bit. Change the 'Graphics API' option in settings to Mantle after starting the game and then re-start the game.
EDIT: The biggest performance spikes will be seen on systems that feature low- or mid-range CPUs. If your PC rocks a nasty CPU but a cheapie graphics card, you won’t have nearly as much to gain from the update.