Yep, just what I thought.
R9 295
AMD. That's why.
Decent enough hardware, but terrible OpenGL drivers on Windows. Always have been, from the very first Catalyst release until today. They've always had bad Linux drivers as well. Strangely (from what I've heard, I don't have one to verify), the Mac OS drivers seem to be halfway decent, but that may have to do with Apple having a hand in their design.
I'm not sure if OpenGL drivers are just hard to write and they're not up to the task, or (more likely), they don't dedicate very many resources to it, since GL has always been the domain of professional design software, alternative OSes like Linux that ATI barely cared about, and a small handful of games -- most of them by John Carmack. If you're playing a non-Direct3D game on AMD/ATI, you're going to get suboptimal performance.
Crossfire is especially problematic with their GL stack and is probably making your performance worse instead of better. Some supported titles have special handling in the driver to use a crossfire mode that works with them, but since I doubt COH is on that list, the driver is using the generic support which is just bad. If the driver will let you, I'd try disabling crossfire for COH and forcing it to use the primary GPU only, and see if it helps.
The issue is worse with COH than some other games because COH is very draw call intensive. It was designed for the previous generation of hardware, where the number of draw calls wasn't so important because everything had to use the fixed function pipeline anyway, and polygons and fill rate were the limiting factor. Most newer games, especially the very pretty photoreal ones, use high poly count models with massive high-res texture maps and computationally intensive shaders, but render relatively few models at a time. All of the fine detail is baked into the texture and normal maps, so they need unique textures for everything, which is why games like Black Desert are a 40GB+ download.
COH on the other hand, draws a large number of tiny objects. That gave map designers much more flexibility to easily add small details (even graffiti and road markings are decals drawn on top of a bigger object in real time), but with poorly optimized drivers like AMD's, means that the game spends most of its time waiting for the OpenGL driver to send commands to the GPU. If you have any performance monitoring software, you'll probably find that the GPU is barely breaking a sweat, and that the COH process has a second thread (this is the GL rendering thread) which is maxing out a single CPU core and is spending the majority of its time inside of opengl32.dll!glDrawElements.
That isn't really an engine problem -- the Ultra mode engine uses VBOs, vertex programs, hardware-assisted occlusion queries, and most of the latest tech -- but rather assumptions made in the art asset and level design, which are a lot harder to fix.
For many years while the game was active I always recommended nVidia for COH players for exactly this reason. You pay more for comparable hardware, but it just works better with OpenGL. Even some of the newer Intel HD chipsets would probably work better, sadly.
