Futuremark cooked up an API Overhead Feature test for its 3DMark Benchmark which allows the user to test performance of DirectX 11 (single-threaded and multi-threaded), DirectX 12 (For Windows 10 only) and Mantle API for AMD-based systems. This is the first 3D Benchmark that is providing tests for these API.
Futuremark explains how the API Overhead Feature Test works. They’ve explained:
The 3DMark API Overhead feature test is the world’s first independent test for measuring differences in DirectX 12, DirectX 11 and Mantle API performance. DirectX 12 and Mantle let developers code “close to the metal.” And though it’s natural to DirectX 12 and Mantle let developers code “close to the metal.” And though it’s natural to think of the GPU, the benefits of APIs with lower overhead are actually achieved by making better use of multi-core CPUs to streamline code execution and eliminate software bottlenecks, particularly for draw calls.
A draw call happens when the CPU tells the GPU to draw an object on the screen. Games typically make thousands of draw calls per frame, but each one creates performance-limiting overhead for the CPU. As the number of draw calls rises, graphics engines become limited by API overhead. APIs like DirectX 12 and Mantle reduce that overhead allowing more draw calls. With more draw calls, the graphics engine can draw more objects, textures and effects to the screen.
The 3DMark API Overhead feature test measures API performance by making a steadily increasing number of draw calls. The result of the test is the maximum number of draw calls per second achieved by each API before the frame rate drops below 30 fps.
Those with Windows 10 Technical Preview can check out the DX12 performance for their graphic cards, but for others who want to wait till retail Windows 10 operating system, you can try the single-threaded to multi-threaded DX11 and AMD Mantle API for those with AMD based gaming setups. For more information and to check out the benchmark, do click here.