Hey! I'm building an actually not garbage PC now and am aware of the RAM compatibility and stability issues with Ryzen. I will be getting an Asus X370 board, G.Skill Trident Z RGB 3200 MHz CAS 14, and a Ryzen 7 1800X. Been pretty curious what the highest and most stable RAM speeds are with this kind of setup. Thanks!
3200mhz is the fastest you'll get. Also make sure your RAM is on the QVL list. Flare series is guaranteed compatible with Ryzen, unlike Trident series.
I was able to nudge it up a bit, but the increase in timings weren't worth it
Which asus board? Crosshair or prime?
Depending on quality of your CPU IMC and RAM bining you can expect more than that.
I can speak for C6H.
As for numbers - 3466@14-14-14-28 1T is achieved by many (for single rank DIMMs, dual rank is limited to 3333). This is pretty sweet spot as for now - good linear speed and low latency.
Mine (ryzen 1700 + 4x8GB trident Z) can run 3600@16-16-16-38 stable.
Lower timings are possible but effort to stabilize it is not worth it (small speed gain, voltages go up, cold boot becomes more prominent).
But you would need to read how to setup BIOS as it would not run like that out of the box - best place is OCN forum.