Question ASRock Killer SLI won't boot with a Ryzen 3700X, no post

[Yggdrasilbury]

I’ve updated my BIOS to 5.40 in order to be able to be able to replace my 1800X with a 3700X, following the instructions on

https://www.asrock.com/MB/AMD/X370 Killer SLI/index.asp#BIOS

Now my fans start spinning up att full blast as soon as I boot, keep spinning at pretty high rate, and spin up cyclically from medium intenstity to full blast, almost like they would in a boot loop. They never stop spinning unless the system sleeps, even with no processes running. Other than that, the system is running normally.

When I try to switch to the 3700X, the system doesn't boot or post. (I've reset the CMOS, booting with just RAM stick, to no avail).

When I switch back to the 1800X, the system boots just fine, except the fans spin in that weird way.

Also, the system is now seeing two of my RAM sticks as 8GB each, not 16GB. Previously, they were being properly addressed.

Any idea what’s going on?


System:
Windows 10
ASRock Killer SLI
Ryzen 7 1800X
64GB RAM
RTX Titan Corsair CX750

 

[Lutfij]

Do you have a POST speaker connected to the motherboard?

What BIOS version were you on prior to flashing to version 5.40? Did you verify that the Ryzen 7 3700x was working if you'd purchased it used/second hand? Even if the processor was purchased brand new, there were instances of AMD Ryzen processors coming dead on arrival, and needed to be RMA'd, even as much just the integrated memory controller(IMC) being faulty out of the box.

I've reset the CMOS
You're advised to disconnect from the wall and display, remove the CMOS battery, press and hold down the power button for 30secs, then replace the battery after 30mins.

64GB RAM
+
Also, the system is now seeing two of my RAM sticks as 8GB each, not 16GB.
Can you elaborate on your ram loadout?

Corsair CX750
Is the green labelled unit? How old is the PSU?