Prime X370-PRO owner here as well! I've got my Ryzen 7 1700 running stock with Wraith Spire cooler, waiting on the AM4 bracket for my MasterLiquid Pro 280. Seems like that will be mid-April at the soonest.
I got a fresh install of Win7 put on my Crucial SSD, I also set up a software RAID 0 with my 2 2TB Toshiba drives, works flawlessly so far. After a rough ride getting everything going, it's all now up and running smoothly. All I've done so far is download and install software and games, getting all my stuff set back up, but it's been ultra smooth. I'm really impressed with this processor so far, the desktop feels very snappy and smooth.
I haven't touched the RAM yet, but I've got a good Samsung B-die single side set of RAM to use, so I'm hoping to get up to about 3000MHz. To be honest, I don't need blazing RAM so whatever I get with the least amount of fuss and instability is what I'll use!
I'll leave everything at stock until my bracket arrives, then I'll start pushing the system. Until then I'll game and use it stock. Hopefully tonight I'll be able to game on it and get a feel. Finally!
Edit: Those with issues, are you using clean installs of your OS or not?