Blank textures are often added to intentionally gimp performance, adding tessellated objects to gimp AMD cards like this is frequent.
As someone who's stuck using an AMD, that's a fucking shitty thing to do.
It doesn't hurt the new RX cards as much as it used to because they sort of cheat and ignore tessellation, but older AMD cards get fucked by it because it takes them a while to process tessellation since it's supposed to be done on Nvidia's CUDA, The Witcher is quite bad for it.