Using my box test of over 100,000 boxes, I can compare performance in the new engine using OpenGL and Vulkan side by side. The results are astounding.
Our new engine uses extensive multithreading to perform culling and rendering on separate threads, bringing down the time the GPU sits around waiting for the CPU to nearly zero.
Hardware: Nvidia GEForce GTX 1070 (notebook)
OpenGL: ~380 FPS
Vulkan 700+ FPS. FRAPS does not work with Vulkan, so the only FPS counter I have is the Steam one, and the text is very small.
Vulkan clearly alleviates the data transfer bottleneck the OpenGL version experiences. I am not using a depth buffer in the Vulkan renderer yet, and I expect that will further increase the speed. I'm very happy with these results and I think exclusively relying on Vulkan in the future, together with our new engine designed for modern graphics hardware, will give us great outcomes.