Ryzen 3000 series support

Thank you for sharing. BIOS 3.52 didn't help in my case either.
Add Seasonic Focus Gold 450FM to the list of power supplies this motherboard doesn't like with a R3600. Antec Earthwatts 380 POSTed just fine and I used that to install 3.52 instead of swapping to a R1700 like I did many times before.
Returning both of my B450 ITX/AC Fatal1ty boards to Newegg today.
BTW tech support never got in contact with me after filling the form on their website (not in any spam folder either). I still have faith in their ATX-sized boards, but for this project it's going to be Asus.

sebastianer wrote: I think I'm not the only one with this issue, some guy in Reddit with the same motherboard and I think CPU, told me that when he finally got a successful POST decided to leave his PC on 24/7 disabling sleep.

Hi sebastianer,

TLDR: I'm having the same issue using the same board/CPU. I updated to BIOS 3.50 with no luck on resolving it. Did you ever have any luck with yours? Please let me know if you were ever able to get it POST normally or if you ended up switching hardware. Thanks!

The whole story:

I am having exactly the same issues. I have the B450 ITX board as well, I bought it new, with BIOS v. 3.30 installed already so I built it together with the 3700X right from the start. It took a a couple of reboots the first time with the GPU fan spinning full speed, CPU/Case fans not spinning at all, which scared the sh*t out of me. After a couple reboots it POSTed and like you said, once it POSTS it stays on.

I had hoped that was the end of it. But the next day i went through the same thing except it took an entire hour before I was able to get it to POST. Once I got it to POST it seemed to be able to POST more frequently in succession, so I decided to install the newer BIOS update v. 3.50 hoping it would resolve the issue, but here I am today going through the same thing.

Bol wrote: B450 gaming ac-itx, ryzen3600, new bios.(3.51)

Don't forget to post here:
https://www.reddit.com/r/ASRock/comments/cm0shy/tech_support_sent_you_a_beta_bios_post_it_here/?sort=new

Bios returned to 3.30 as its the most bootable.

I tried 3.30 today, didn't work for me at all.

Here's what others are doing, sorry Asrock:
https://www.reddit.com/r/ASRock/comments/cx4zui/switching_to_asus_fixed_all_my_problems/

B450 gaming ac-itx, ryzen3600, 7700hd(temp) silverstone sst-sg500 psu.
I had my reply yesterday from asrock technical support including a new bios.(3.51). Installed and tested this morning and issue still persists.
system fires up and fans spin, reboots and hangs until powered down.
Occasionally about every 10 reboots i will get a bios screen
Ran downclocked and settings dont stay applied.
Bios returned to 3.30 as its the most bootable.

Incidentally, all bioses I have installed have been overwritable to previous versions.
Additionally previous generation cpu ( 2200g and 200ge ) ran fine on bios versions upto 3.51.

Hello everyone!
I have a post and reboot problem on my system containing next parts: fatal1ty b450 gaming itx/ac, ryzen5 3600, kingston a1000 m.2 480gb ssd, Kingston hyperx 2x16(hx424c12pb3k2/32), powercolor rx 580 8gb red dragon, sfx chieftec 650w (csn 650-c).

Cold post work in 90% of the time, system usually boot to windows in 30-40 sec. But reboot are usually go into bootloop, same as sleep mode. Even exiting bios can start bootloop.

Current bios is 3.5

Would be very grateful for any advice.