[SOLVED] Rebuild anomaly ?

[Schewe]

This has been a maddening situation that I've finally narrowed down to a definite cause, now I'm just hoping somebody could tell me the 'why'.

The gist of it is: new motherboard, new CPU, same PSU, same case, same accessories, etc. Install it all and get a no-boot situation with alternating CPU and DRAM lights.

After many different trials and tests I've discovered it's my PSU that the new build seems to disagree with-- I word it this way because my previous motherboard and components has absolutely no issue with it.

So now I'd just like to know what the deal here is. Why my test bench CX550M power supply boots it up without issue, but my AX1200i causes the above mentioned problem. Surely if it was a short, my older board would have the same problem?

I've already tried reseating any connectors and tested both in a breadboard/minimal configuration. I could just use the smaller PSU in the meantime, but I'd still like any possible solution to avoid this.

Old board/CPU:
Intel i7-6700k
GA-Z170X-Gaming 7

New:
Ryzen 7 3700x
Aorus B550 Pro

"Problem" PSU
Corsair AX1200i

Test Bench PSU (successful boot)
Corsair CX550M

GPU, RAM and additional accessories are irrelevant to this situation

 

[KennyGilbertS]

Have you tried doing a breadboard configuration with the AX1200i? See if that worked when put outside the case?

I have had similar situation happen to me, but i didn't get to know what caused it, and ended up just switching power supplies.

The funny thing is that in my case, i had got it working by changing ram modules, which makes the problem even weirder.

 

[Schewe]

Yup I have tried both in a breadboard setup, always the same results-- one fail, one success. I had tried numerous different RAM sticks before I had traced the issue to my PSU as well.

I have a feeling the age of the power supply plays a big factor in the situation, but nothing seems to explain why it would work fine with my previous build and not this one. Unfortunately I imagine I'll need to go the same route you had-- buying a new PSU.

 

[geofelt]

Is there a bios update for the motherboard that might address the issue?
Modern motherboards and power supplies work very hard to lower power usage.
There may be some default bios settings that are causing problems.
Perhaps deselect the most aggressive power options.

 

[Schewe]

Thanks for the suggestion. Updated BIOS and tinkered with some options. I thought I had a eureka moment when I saw the 'power loading' setting on 'auto' and tried with it enabled-- no dice. The PSU fan does spin up briefly when turning the PC on, followed by the aforementioned blinking debug lights.

Looks like I'll contact Corsair and see if they have any guess as to what may be happening internally with this specific PSU + board combination.