If it isn't the latest then try updating. Be sure to use the instant flash option, it is by far the safest method. Download the instant flash BIOS file from your board's product page and follow the instructions. 

You have done a great job troubleshooting so far. Let us know how the update goes (if you have not done so already).

I had similar issues with my Taichi (random hanging then resuming) until I did a fresh install using a newly downloaded Win10 installation medium. The problem seemed to be coming from the Windows 10 anniversary update. Whenever I tried to install from my older media it would immediately give me issues once the anniversary update installed (after OS installation). By downloading a fresh install medium you get the update bundled with the install and for some reason that worked for me. I have been stable for months now with no crashes, BSODs or freezing. See my sig for my overclocks (except RAM that proved unstable over time so I am at 3200 now).

The other possibility is RAM as you mentioned. If you can get your hands on some other RAM to test with (preferably from the QVL) that would help nail it down. Ryzen has proven a tricky beast for a lot of people, in the end it is worth it however. I am loving my Ryzen system 

It's 2am here now so I am off to bed but good luck and let us know how you fare 

This ^

Once installed, set Ryzen balanced power plan, disable USB and Pcie power savings inside the plan.

Boot to UEFI, disable CPU C6 state. Reboot and let us know how it did.

Cheers.

It doesn't makes sense, but I guess if it only crashes at idle, I'm guessing Windows's default balanced power plan lowers the CPU frequency and voltage a bit too much to conserve power/reduce heat. I'm wondering if disabling Cool and Quiet, and C6 State would also stop this from crashing at idle as it'd keep the voltage from dropping so low.

John, you can lower the min CPU power state inside the plan to whatever you want. I have mine set to 20% and my CPU idles at 1550Mhz and goes all the way up to my max OC.

In my findings, theres seems to be a problem when Windows puts some devices, including the CPU cores, in a low power state mode.

You want to leave C&Q enabled for the automatic CPU power savings. Only disable C6 state to not let Windows shutting down your CPU cores.

I'm aware you can change it, but by default it's at 5%. This person's experiencing crashes at idle. My train of thought is Windows may be dropping the voltage too low.

Your findings may be correct and the Ryzen Balanced Power Plan by default prevents the frequency from going below 90%, instead of 5%, thus hopefully fixing the problem.

YOU may want to leave CnQ and C6 enabled, but it's not mandatory. While troubleshooting, it's sometimes necessary to give people additional options and suggestions to try should other ideas fail.

5% default is the Windows balanced power plan, not the AMD Ryzen one. The AMD tuned power plan is 90% minimum, so you need to tune it if you want lower frequencies at idle.

I agree with you about suggestions, but try one at a time because all suggestions at once is a mess in the end, and you didn't find what was the real cause of the instability.

I suggested to try all of that at once because it's the only combination which worked on my end to avoid random freezes and mouse stutters at idle and after long sleep periods.

Cheers.

I fear you may have combined two suggested methods of fixing the crashing based on my thoughts and ramblings. If you install the AMD chipset drivers, it'll install the Ryzen Balanced Power Plan. If you're not overclocking the CPU and are using that specific plan, you will not want to disable Cool'n'Quiet or C6 State options. Those were alternative suggestions if the Ryzen plan didn't work; a "one or the other" scenario, but not both. Sorry if my thought process wasn't able to be followed. :)