I forgot what I did when I had the same issues. Go and set Power Down Mode to disabled, it should fix your issues.
Revo uninstaller remove old AMD Chipset Drivers
Install AMD Newest Chipset Drivers 18.104.22.1683
USB BIOS Flashback CROSSHAIR-VI-HERO-ASUS-7501.zip
Only Disable Power Down and DRAM ECC
DRAM 2400MHZ No use D.O.C.P All default
Still got BSoD
But after use AMD Newest Chipset Drivers 22.214.171.1243
Bios 7501 always BSoD →become sometimes BSoD
Are you running the Windows balanced power plan or Ryzen balanced?
My BSODs seem to have stopped after either running chkdsk /scan and chkdsk /F bacause i had some errors or switching to Ryzen balanced plan and not lowering minimum processor state from 99%.
As an update for when I had the Q-code 8 boot issue. I seemed to have gotten it to be "stable" after flashing 7306 a bunch of times and (maybe related) replacing my corsair H100i liquid cooler with Noctua NH-D15. It does happen when I reboot from time to time but most of the time, it boots up just fine. Still though, the moment I upgrade the bios to 7403, it's Q-code 8 all day everyday when booting. Sometimes it does end up actually booting on 7403 but most of the times, it doesn't. And yes, I disabled ECC everytime.
At this point, if the next Bios update still does this Q-code 8. I am gonna RMA my motherboard cause at this point, I am 90% certain there's something wrong with the mobo's BIOS.
I almost want to blame Asus's shingians with trying to enable PCI-E 4.0 on X370 boards and then when AMD removed it by changing the micro-code, weird stuff started to happen. But we will see when the next BIOS gets officially released.
By any chance you could try turning the PC on with Safe Boot button and skipping the Bios? If we can both verify that code 8 doesn't happen with Safe Boot, then it is 100% something ****ed with the BIOS.
It is the only way I can turn on my PC (reseating the CPU works too), otherwise it is Code 8.