That's what I would recommend. You won't see a huge difference in visual quality but there will be some, similar to the improvement brought by anti-aliasing. A 1070 should be able to run games at that resolution pretty well, if not go look at some of the other options in DSR, and try a slightly lower up-res. The amount of fps you will lose will vary per game, some you may not lose any some you may lose alot, it would be easiest to just try it out with fraps or something.
Linus has a pretty old video that covers how to do it before DSR was an actual thing and you had to mess around with other settings to run at higher resolutions, but the video still shows off some of the benefits pretty well.