For some reason my motherboard no longer works with Ryzen 3000 series.
I originally used a 1600x for about two years and switched to a 3700x which I ran for well over a year, I switched batch to the 1600x for the past month while awaiting some parts and now I'm repurposing it for another rig.
I put in the same 3700x and it always stops on debug code 3b and restarts. I tried a spare 3600 and its rebooting on the same 3b debug code. The 1600x still works.
I tried both bios v5.30 and v5.40, any ideas?
This is what Code 3b means: code 3b = Post memory pch initialization is started.
First do a CLEAR CMOS on your motherboard to put the BIOS back to factory default or Optimized defaults and see if that fixes your issue.
It is possible when you switched processor it changed a setting(s) in BIOS that made the 3700x incompatible. By doing a CLEAR CMOS will fix that issue. Do it with the 3700X installed.
If you still have the same Trouble code, remove all RAM Sticks and just install one RAM Stick and see if it boots up plus disconnect all hardware that you don't need to boot into Windows.
Also you need BIOS Version P5.40 for your 3700X to work and boot up. According to ASRock you need to have the latest AMD All-in-One VGA CHIPSET (Version 18.50.16.01) installed before upgrading to that version if you upgrading from an earlier BIOS version: http://www.asrock.com/MB/AMD/Fatal1ty%20X370%20Gaming%20K4/index.asp#BIOS
Sounds like a BIOS issue. Possibly it got corrupted. If the motherboard was defective I would believe the same error would occur with the 1600 and 3700X processors. But since it works with the 1600 processor sound like a BIOS issue.
Try reinstalling the BIOS with the 3700X installed and make sure you download the latest ALL In One VGA AMD Driver CHIPSET and install it before updating the BIOS again if possible. Also make sure you install BIOS version P5.40 which is the BIOS that supports the 3700X.
I cleared bios with the 1600x and with the 3700x installed. It never POSTed with the 3700x or 3600.
I tried both bios v5.30 and v5.40 with a single RAM stick for both the 3600 and 3700x, same error.
How could this mobo work with the 1600x and not the 3000 series any more?
Try installing the 3700X and then install again BIOS version 5.40 or newer BIOS version and see if it is recognized.
The only I thing I can think of is that the BIOS is corrupted.
Otherwise I suggest you open a ASRock Support ticket and find out if your BIOS chip on the motherboard is defective or not.
I cannot install any bios with the Ryzen 3000 series installed because it will not POST with that installed.
I've already tried reinstalling both bios v5.30 and v5.40 and neither work. If I attempt to install a newer BIOS I will lose all functionality with the Ryzen 1600x and thus bricking the motherboard... the only processor that the thing will currently POST with is the 1600x therefore I cannot install a BIOS that does not work with the 1600x (namely, anything newer than v5.40).
Yes, I understand that a newer BIOS version than 5.40 will not support your 1600x processor.
But BIOS for the 3700X to be recognized you do need BIOS version 5.40 installed not 5.30 according to ASRock CPU Support list.
Anyway, doesn't matter.
You need to open a ASRock Support ticket and see if you need to RMA your motherboard to have it checked or they can offer some suggestions in getting your motherboard to start supporting again the 3xxx series processors.
Seems like the BIOS chip on the motherboard went bad or got corrupted and needs to be physically checked.