GA-AB350-Gaming 3 - can't clear CMOS (or dead CPU?)

[LatvianAce]

My problem is following: after BIOS update and attempted overclock I can no longer get my PC to boot or to get into BIOS menu. Red diode indicating CPU problem stays lit.

What i did:

I upgraded my BIOS to F7b in hopes of getting my Corsair Vengeance LPX 3200 RAM to run on 3200Mhz. It was previously stable on 2933, together with Ryzen 1600 overclocked to 3600Mhz.

After flashing bios I successfully rebooted, but had to punch in all my overclock settings as they were cleared. I did the following steps:

1) Enabled XMP and chose the only available preset that set the RAM frequency to 3200.
2) Increased DRAM voltage to 1.35V, which is recommended by Corsair.
3) Increased the CPU multiplier to 36 to set CPU frequency to 3600Mhz.
4) Set Dynamic Vcore to +0.12.

Save and exit.

It won't boot and won't let me into BIOS. Red light indicating CPU problems stays lit.

What I tried:

1) Restarting multiple times hoping that the BIOS will kick in after failed overclock.
2) Tried clearing CMOS by using the jumper.
3) Tried clearing CMOS by removing battery.
4) Tried clearing CMOS by doing both of the above and leaving it overnight.
5) Supplemented the above by removing RAM and GPU.
6) Tried to force dual bios to kick in by holding the power button while the system starts and then restarts again.
7) I even reseated  the CPU for no good reason.

Nothing works. Have I somehow fried the CPU? Motherboard? What is this sorcery? This is the first system I'm trying to overclock, so not much experience here.

[BoNfiRe]

As you've done the clear CMOS and it's still not booting, I assume something is dead. Maybe try a single stick of RAM in all four slots to make sure it's not that. Also, how did you clear the CMOS via the jumper? Just fyi, add the jumper, plug in power and press the power button. Power down, remove the jumper, plug in the power again and see if that helps.

Also, as it's a dual BIOS machine, just switch it over to the other one!

[LatvianAce]

It's a dual BIOS motherboard, but there is no manual switch. I tried the methods I found to force the backup bios, but they did not work (or it did, but the CPU is dead or something).

[BoNfiRe]

I don't have the board, and assumed it had the switch. Have you tried removing the RAM and tried all slots? Only other thing I would suggest beyond that is RMA. But what's failed is an unknown, it's more than likely the board.

[LatvianAce]

Just wanted to give an update for this -

I returned both the board and CPU together for warranty checkup and service.
It took them a fricking month to come back saying that both board and CPU was OK, but they've flashed the BIOS (don't know to what version).
Still, when got my rig together, the same problem remains - no video signal and CPU diode remains lit. So I have to assume that it is one of the other components, likely my Corsair Vengeance LPX 3200Mhz RAM (cmk16gx4m2b3200c16r) somehow not being compatible any more after upgrading from F6 bios.

Judging from posts all over the internet, I am far from the only one with the "no post, CPU diode" issue, many with the same high end Corsair RAM. The proposed solutions are various and inconsistent, and so far I've been unable go fix anything, and there are no guidelines from Gigabyte. I find this quite ridiculous.
Will likely switch to a board from another manufacturer

[absic]

Ouch!
Sorry to read about your issues and the attempts you have undertaken to try and resolve them.

If the CPU & Motherboard have been tested and are found to be OK then the best advice I can offer is to try and pin down exactly which other component is causing the problem.

When you were doing your initial troubleshooting, after clearing CMOS, did you try restarting with only one stick of RAM onboard, rather than the full kit? If not, then I would probably do this. Also, in the first stages of testing, remove all peripherals except for the keyboard from the USB ports. Make sure that you do not have any SATA devices attached as well, as this can help narrow down where the problem is coming from.

So, to recap, disconnect from the main power sockert. Clear CMOS again. I would also remove the battery and leave it for several minutes.
Press the power button on the PC case a couple of times to make sure that ALL power has drained from the system.
Reinsert the battery.
Only have the CPU, One stick of RAM the GPU (Connected to the monitor) and the keyboard attached to the motherboard.
Reconnect the main power lead and then try to start up.

Hopefully, with this minimal setup, the system will POST and you can get into BIOS.

[LatvianAce]

Thanks for the suggestions.

I just tried using the board with different PSU, and just a GPU and single RAM stick (in multiple slots). No change. As soon as I power on, CPU led indicator lits up, while everything else seems to be working fine, but no video signal, no BIOS screen.
It does the same with no RAM inserted at all. And yes, I tried clearing CMOS again.

So it would be logical conclusion, that either RAM or GPU is causing the issue (although it still does not explain the CPU led). The GPU is working fine in another board. Unfortunately I have no other DDR 4 memory or compatible board to test the faulty memory problem, but somehow I find it hard to believe that both of my new Corsair sticks mysteriously died after updating BIOS on the board.

[absic]

As the memory controller is an integral part of the CPU, if there is an issue with the RAM it would show up first in the CPU not being able to function correctly, hence the CPU led staying on as the system tries to POST.

The only way of knowing for sure, if it is the RAM modules at fault, is to try and get hold of a cheap DDR4 stick of RAM or see if you can borrow one from another PC. If I were in your position I would probably get hold of something like this: https://www.scan.co.uk/products/4gb-corsair-ddr4-value-select-pc4-17000-(2133)-non-ecc-unbuffered-cas-15-15-15-36-12v-single-stick-d just to see if I could get the board to power up properly.

[LatvianAce]

So, here is another update. I've been using my backup PC all the time, and finally got about to buy a cheap DDR4 stick and test this system. It works. But as soon as I plug in one or both of the fancy Corsair Vengeance sticks, even together with the new stick, the the old problem return and I cannot even get to BIOS, no matter in what slot they are. I even rolled back the BIOS to F6 thinking that might fix it but no success.

Could both of my RAM sticks really be fried? No idea how to test that.

[ElectroStingz]

Hello,

The newer BIOS updates something related to the memory mangement, AGESA. This can alter memory compatibility meaning it can cause the previous memory to stop functioning.

The odd part is that you mentioned going back to the previous bios and it no longer works.
If the XMP setting over-volted the memory sticks, yes it can cause damage.

Do you know anyone that can try the Corsair LPX sticks?