For some reason newest version of Rhino7 and Enscape 2.9.1 creates blurry renderings, both preview and actual renderings (rendering quality Ultra). Is this known issue or is there something wrong in my work station. My graphic card is not the best neither latest (Nvidia Quadro K2200).
Thanks a lot for your message, I’m sorry to hear about that, and welcome to our Forum! 
In the first instance, when the preview itself is blurry, try going into the performance tab and disable “Automatic Resolution” and “Automatic Upscaling”, disabling the latter should then resolve the blurry renderings as well - if not, please send me a rendering of yours so I can see the results.
And, make sure you also update your NVIDIA drivers:
https://www.nvidia.com/Download/index.aspx
When you disable these two features though, then you may experience performance issues. Or errors. Either when rendering or when walking through the project - so perhaps only disable the “Automatic Resolution” feature if the preview itself can be a bit blurry, but you want more sharp renderings.