Windows 10 upgrade - graphics quality

Based on requirements from January, I upgraded my PC from Windows 7 to 10, yesterday. I have a reasonable spec PC, though since the upgrade the graphics quality of Zwift has become quite poor, even using 4k setting. Can anybody offer any advice as to why this may be?

No reason why changing OS should affect anything, but would need more info to be able to help properly:

  1. What are your full system specs?
  2. What is it that you are considering ‘poor’ compared to before?
  3. Post the results from a log file uploaded to Zwiftalizer.