Linux

I've upgraded to an R9 380 last week and am quite satisfied with the performance. My framerate is great (even getting 100+ fps on more modest settings, about 65fps on highest settings if I recall correctly), and I can now run two clients very comfortably. I'm on a 4k screen and high resolution as well. I'm using the open-source amdgpu driver. Arch Linux, kernel 4.5, wine staging (1.9.something I believe it was).

Only downside is that the fans indeed make some noticable noise, but I'm coming from a passively cooled card prior to this (and passive PSU) and I'm rather picky about noise anyway.

If your using proprietary drivers or Opensource drivers (with normal wine) , the limit is the CPU, not the GPU.

The D3D->OpenGL conversion from wine will happily eat a whole core and that's the limit. If you reach 100% of that core with a Radeon 7970, you will get about the same FPS even with that new 2000$ Radeon Pro Duo.

If you want to get more power from your card, especially AMD, you should give a try to the ixit wine patch to use the Direct3d state tracker directly. You get rid of the "conversion" thread and way more FPS.

For information, my old Radeon 7970 do:

Will all settings to high:
220 fps in station
175 fps in space with nothing really
+-100fps in a pos full of junk (and all the junk in the camera)
+-65fps (with two client in a asteroid belt)

You use Gentoo so the "wine-a-holics" contain a wine-9999 with proper patch (you have to enable d3d9 use for Mesa and Wine).
After you go in winecfg, in staging and check "Use native direct3d9" or something that look like that.

Note : If you have a got card and wine eat 100% of one core, overclocking will improve fps. I did run my AMD FX-8120 to 4.2Ghz with greatly helped until I switched to native d3d9 and put clock back to normal.

2: For the coil whine, if it's actually really coil whine, you can't do anything but finding the part emitting the whine and RMA it (if they want to exchange it and hopefully the replacement will not have the same...).