Some memory speed benchmarks with a Ryzen 1700 @ 4.0GHz and a 1080 Ti, 2666 Auto vs 3200C14 vs 3466C14 tweaking sub-timings. Timings and settings used in the comments. : r/Amd
AMD Ryzen 5 5600G RAM Speed Benchmark | 3000MHz vs 3200MHz vs 3400MHz vs 3600MHz - YouTube
CPU Performance - Zen and Vega DDR4 Memory Scaling on AMD's APUs
Does RAM Speed Matter For Gaming On AMD Ryzen? Testing Memory Up To 4000MHz | bluelionsoft.com