PC keeps rebooting, no display - z370 aorus gaming 2.0

[kryspin34]

SPECS:
CPU: i9 9900k
GPU: Gigabyte 1060 3GB WindForce
MOBO: Gigabyte z370 Aorus Ultra Gaming 2.0
RAM: Patriot 16GB 3200MHz Viper RGB LED White CL16
Pump and reservoir: Enermax Neo Changer 400ml
CPU Block: EK-Supremacy EVO RGB
Radiator: EK-CoolStream PE 480
Fans: 4x Corsair LL120
PSU: Thermaltake Toughpower Grand RGB 850W
Case: Thermaltake P5

So, I've done this build. I did leak test couple days ago and it was fine. Today I got my CPU shipped, mounted it in, did another leak test, mounted all the cables and the PC doesn't turn on. Fans on the GPU, corsair fans and the pump are working, but the PC shows no display and reboots every 10 seconds. On the mobo it mostly shows red light on the VGA, but right before the PC shuts down it switches to the red CPU light. If I take off rams, then it blinks between CPU and DRAM and couple seconds later it stays on CPU and speaker starts beeping. The mobo has these leds on it, and they don't work. Only after I turn on the PSU, not the PC itself, the leds flash once. The only time I got the led working was when I plugged only one stick of rams to the mobo, then the red light stayed on the CPU warning led and speaker was beeping, however I cannot get the same result after doing it again. I tried plugging rams into different sockets as well, but it makes no difference. RGB on rams works fine. I also tried reconnecting psu cables, and it didn't help as well. What might be wrong?

 

[bignastyid]

What bios rev is the motherboard running? Z370 boards require a newer bios for 9th gen cpu support.

 

[kryspin34]

Thanks for the answer.
How can I check it? On the motherboard it only says Rev 1.0

 

[bignastyid]

Thanks for the answer.
How can I check it? On the motherboard it only says Rev 1.0

I don't think it is written anywhere on the board or the box.

Possible it's a DOA piece of hardware, but bios revision is more likely.
Since the board doesn't support usb bios flashback you'll need to install an 8th gen cpu(cheap celeron g4900 would work) to update the bios to support the 9th gen cpus. Another option would be to return/replace the Z370 with a Z390(supports 9th gen out of the box).

 

[kryspin34]

The celeron g4900 option seems doable, and the motherboard most likely has old F2 bios version, since the store I bought the mobo from offers bios update, just didn't think that through when ordering. However, I don't to waste money needlessly, so how certain are you, that these syptoms occurs when bios is too old for the cpu? That seems very logical, just don't want to buy celeron and find out that it's still not gonna work.

 

[bignastyid]

With out the proper microcode the bios can't communicate with the CPU and will not complete post. The microcode for 9th gen was not added til bios rev F10 and then optimized in F11.

 

[kryspin34]

I'll give it a try, thanks for the help. I should be able to get the celeron tomorrow and check it out.

 

[smorizio]

on the mb there will be a small sticker on the bios chip for the bios rev of the mb.