Games I have seen a noticeable improvement in FPS and in general fluidity, if I use BF1 for a example I have gone from around 100 - 115 FPS on average to being more less pegged at 144FPS. However, I guess some of the smoothness can be attributed to moving to a 165Hz screen. Also game and stream at the same time now without being CPU limited as before it at a notable impact on the games and in some cases it was unplayable. To add to that in 3D benchmarks which I know are not real world examples, the 7900X monsters the 6850K my Timespy benches are a good example of that as well.
In Photoshop, Lightroom, Premier I've seen a subtle but noticeable improved in speed, like applying effects etc...
If you need any more information let me know.