People have been yelling ooh ooh scary scary since Sandy Bridge and the only problem has been in their imagination. Th governing standard for RAM is JEDEC and the JEDEC specs do not include Intel's XMP and AMDs AMP so they are considered 'overclocked". And just about very RAM package you can find with be advertised at the XMP / AMP sped and voltages. For Intel, you can go to their XMP page for a "certified compatible" listing if RAM speeds and voltages. And there you will pretty much find that every RAM fazter than 3200 is 1.35 volts/. from the horse's moth' so to speak
http://www.legitreviews.com/what-is-the-safe-voltage-range-for-ddr4-memory-overclocking_150115
Legit Reviews contacted Intel about the safe voltage range on DDR4 memory and we received this response
1.5v is the absolute max we allow for XMP certifications. However, good DDR4 memory will run at 1.35v up to 3200.
Now all that being said, this is AMD and this is a budget level MoBo from Asus.... what may or may not be safe is somewhat immaterial if the manufacturer's won't warrant your product. I would search AMDs AMP certified compatible list and contact Asus for an answer.
I would note that:
a) According to newegg's data that board only supports "Ryzen Processors, DDR4 2666/ 2400/ 2133"
b) Below 3200, you will likely be able to run that RAM at any of those speeds at 1.2 volts
c) Without seeing the SPD data, i couldn't tell you for sure. Check the Gskill site for specific SPD settings