3400 cl14 or cl15 is your best possible outcome, but for the price difference alone vs 2666/3000mhz ram you could add a RX 560 maybe even a 570 on sale or used and out perform it. So we kind of need to know your situation...
Fastest you can get. 3200MHz would be good w/o wasting money. I've read that Samsung memory chips are the most stable with Ryzen. Haven't verified that tho.
3400 cl14 or cl15 is your best possible outcome, but for the price difference alone vs 2666/3000mhz ram you could add a RX 560 maybe even a 570 on sale or used and out perform it. So we kind of need to know your situation...