https://www.reddit.com/r/Amd/comments/64b904/is_my_ram_bdie_gskill_ripjaws_f43200c16d16gvkb/
And the truth is that they run at 3200cl16 without any problems. I bought them six months ago for 125€, and they have not disappointed me. I tried the Dram Calculator for Ryzen and got a decent improvement. They managed to boot at 3466 casl16 1.38v, but they were not stable. That said, figuring out if they are single or dual is a pain. These are micron MFR single. I also have some ballistic 2666cas16 with micron around here, which I read can reach 3200 cas16. I set them to 2933 cas16 without problems at 1.35v. This thing with memory and ryzen I think is the same for Intel, if you want oc you have to go for some good ones.