Well, I've noticed that it's an issue relating to mipmaps that seems to be specific to my GPU model. Tried a bunch of things, including tweaking various settings in CCC and Radeon Pro, installing ENB Series injector (because it injects dx9 functions into the renderer) and nothing helped so far.
One way of solving this would be if I can somehow figure out how to make Freelancer use onboard graphics only, but I'm not sure if that will be possible.
