Is the Mantle API all it's made out to be? AMD has made a big deal about Mantle - a co-developed graphics application programming interface (API) that redresses some of what the company believes to be lacking in DirectX 11. You see, while DirectX is great as a vendor-agnostic API, AMD is at pains to point out that, right now, significant CPU overhead is incurred by having the driver translate commands from the API to ones the GPU can understand and action.

And it's clearly not just about the driver. Modern games ask the GPU to render complex scenes that require the CPU to fulfill lots of draw calls (or commands) per frame. The purpose of these calls is to tell the GPU to draw an object, or to do some new work. The parallel power of cutting-edge GPUs is such that thousands of draw calls are required to keep them busy and efficient, putting the onus on the CPU to mete them out.