Just got my 3700X installed yesterday and wanted to share what I got so far.
Currently using BIOS 7106 on a C6H and like most people mouse doesn't work in BIOS but it doesn't bother me as I've always hated using it in the BIOS anyway.
I seem to get the C5 or 07 error when messing with memory timings. I found it was when disabling Gear Down Mode. I need to keep this on Enabled or Auto. (I'm using GSkill TridentZ 3200 CL14 B-die).
Watercooled with a Heatkiller IV block I'm getting the advertised boost speeds, 4.4GHz single core (though mostly 4.35GHz), and 4.25GHz all core as long as it stays below 70C. Above 70C, all core is 3.9GHz. Max temp is 78C in Prime95 (my 1600x at 4GHz 1.375V was 68C max).
All core voltage seems high 1.35-1.39 according to CPU-Z, and up to 1.406 according to Ryzen Master. With AMD recommending 1.325V for all core, I decided to use a negative offset but doesn't seem to work right. I've just read the previous posts mentioning this could be fixed in BIOS 7201, so I'll give that a try today.
I did get an unusual crash while running Prime95 for about an hour, not sure if it's related to the 3700X. My screen was all blocky colors unable to read anything. I've never seen this happen for the two years I've owned this motherboard. I was able to ctrl-alt-del, so maybe it was video card related.