Hi, I got two of 16GB Patriot Viper Elite II DDR4-4000 for cheap, there's a review of it: https://www.tomshardware.com/reviews/patriot-viper-elite-ii-ddr4-4000-c20-review
In review they were able to get 18-25-25-45 at 4000hz and 1.45V, which would be nice enough for me.
My environment: Ryzen...