Still don't know about gaming in particular with 960EVO SSD because no games on it. However, on my Ryzen build I've used an 840SSD and a 7200RPM hard drive for the Windows 10 installs (playing with installs). And, I used them for other application installs and everyday stuff.
In everyday use, the 960 blows the HD out of the water (we knew that). In addition, the 960 is noticeably faster than the 840 when loading programs and installing software.
By "noticeably faster" I mean that it gets things done so much faster that I can "feel" it without needing to "measure" it. For example, installing a new version of Windows goes far faster. I can just sit there a few minutes rather than go upstairs for more coffee. For example, my Firefox browser seems to "jump open" in a couple seconds (only took a few seconds in the first place).
The improvement is small in the big scheme of things. But, I "feel" I have upgraded with the 960 and am happy I bought it.
All opinion and feelings, FWIW.