Dawn of War III [Steam] arrives on Linux tomorrow and we now know exactly what kind of system is needed to run it, come check it out.
3.4GHz Intel i3-4130
Nvidia 650Ti with 1GB of VRAM.
3.4GHz Intel i7-4770
Nvidia 980Ti with 4GB of VRAM.
AMD and Intel graphics cards are not supported on OpenGL. However, Vulkan is supported on AMD with Mesa 17.1 or 17.2-devel for Intel. Note: Vulkan is currently still experimental in Dawn of War III.
It's likely AMD will gain support for OpenGL in Dawn of War III with Mesa 17.2, going by all the work going into Mesa right now.
Also, Feral are livestreaming Dawn of War III tonight, event is on our livestreams event page. I will be doing a release-day livestream as well tomorrow, which is also listed on that page (as long as there's no sudden issues), you're all welcome to join in if you can download it in time.