There is a (Driver related) problem with NVIDIA GTX980 card's. The Definitive Edition runs at 5fps or even lower, while the classic Version runs like ten times better.
To fix this, open the 'NVIDIA control panel' go to '3D Settings' and search for the entry 'CUDA GPUs' and uncheck the GPU. That's it.

A more detailed guide with pictures can be found here. (German)

https://steamproxy.net/sharedfiles/filedetails/?id=1950101324