AMD doesn't need DLSS because you can lower the settings, use Radeon Boost and get the same frame rate increase while keeping the quality virtually indistinguishably different.
Tech Spot have articles about Crysis 2 and Crysis 3.
Crysis 2: comparison between Extreme, Very High and High settings:
Extreme:
Very High:
High:
Framerate:
Radeon HD 6870:
Extreme 2560x1600: 23 FPS;
Very High 2560x1600: 34 FPS;
High 2560x1600: 41 FPS;
Crysis 2 GPU & CPU Performance Test > Benchmarks: High Performance (techspot.com)
But you can do that on an Nvidia card, lowering graphics settings to give performance boost, then put DLSS on and it goes even higher.