You guys commenting in the negative, need to watch the full video from beginning to end. The Youtuber points out that while it does render in a lower resolution, for higher FPS, what it does not do, is upscale it back to the desired resolution, due to the lack of tensor cores. My guess is that just changing the render resolution from the options menu to something like 720p, would give the same result as turning on DLSS, on such old hardware. I'm tempted to pull out my old GTX 660, to see if I can duplicate what he did.