Mantle drivers

[giveen]

Some info from the AMD forums

http://devgurus.amd.com/message/1302560

That 9x draw call gain means that the card can run more different shaders, and switch between more textures in every frame it draws. As the computing power is getting higher, it became difficult to feed the gpu with enough work using current directx systems. It needs frequent interaction between cpu and gpu. Whit this new low level api this interaction will be 9x faster, which leads to higher gpu utilization.
On opencl it also introduces a significant overhead when you try to enqueue kernels very frequently: lets say if you have 3 ms long kernel, then the actual gpu work can take only 1 ms time, the rest is host-gpu interaction. But on opencl we can organize long kernels around 1 sec execution times, those can utilize the gpu effectively.