Power supply works in any pc except mine

[rodewouw_]

What the title says

So first a bit of context: This is a second hand (unopened) Corsair CX550-RGB I bought for my pc (R9-5950X + NHU12A CB, CPU @ stock in Aorus B550 Elite v2 rev1.2) Everything went just fine until I tested a pair of R9-270Xs that I bought online. After testing both (perfectly fine) I decided to get some Crossfire action and put both 270Xs in. The two vga 8-pin cables were split into the necessary 2x6-pin (So 2x 8pin -> 4x 6pin in total) and it just shut down.

I mainly thought it was a PSU issue, but the PSU works just fine in any other setup (Test 1: i7-3770 + GTX 980, Test 2: C2Q Q9450 + GTX 1660-S) and my current r9 setup works fine with any other power supply, in this case an old TX750 that I had lying around...

Any clues to what could be the catalyst to this?

 

Any help is appreciated and thanks in advance

 

(Also please note that I have tried almost every type of troubleshoot)

[leclod]

13 minutes ago, rodewouw_ said:

I decided to get some Crossfire action and put both 270Xs in. The two vga 8-pin cables were split into the necessary 2x6-pin (So 2x 8pin -> 4x 6pin in total) and it just shut down.

I see one 270X uses max 270W. 2*270W=540W

To this you can add around 150W for cpu & co = 690W

So you can't run that from a Corsair CX550-RGB

Edited May 19 by leclod

[rodewouw_]

6 minutes ago, leclod said:

I see one 270X uses max 270W. 2*270W=540W

To this you can add around 150W for cpu & co = 690W

So you can't run that from a Corsair CX550-RGB

I know but that doesn't explain the wierd behaviour and also the cards would not use the full fat 270 watts per card at startup/idle (It was an immediate shutdown when pressing power)

[leclod]

15 minutes ago, rodewouw_ said:

I know but that doesn't explain the wierd behaviour and also the cards would not use the full fat 270 watts per card at startup/idle (It was an immediate shutdown when pressing power)

I tend to agree.

Second guess would be Y splitter quality.

But if you're asking for weird behaviour and you get weird behaviour, I'd just call it a day.

You've got better things to do and it wouldn't be mind blowing or even working anyway.  

(By the way I don't know how they reach 270W with mb  pcie 75W + 2 * 6 pin 75W =225W ?!)

Edited May 19 by leclod

[DanteCoal]

Simple explanation is that you're overloading the PSU.  A 550w is comically undersized for what you're trying to to do.  A PSU should typically be sized with around 20% extra room left, both for surges in demand, and for future expansion.  That PSU is more fit for a SFF build or an IGPU setup.

 

I'd recommend getting a larger PSU, something around an 800W fully modular unit is pretty affordable and would do everything you need.

[Spotty]

2 hours ago, leclod said:

I see one 270X uses max 270W. 2*270W=540W

To this you can add around 150W for cpu & co = 690W

So you can't run that from a Corsair CX550-RGB

R9 270x is only 180W TDP.

https://www.techpowerup.com/review/amd-r9-270x/24.html

https://www.techpowerup.com/gpu-specs/radeon-r9-270x.c2466

Two cards would be 360W. Plus rest of the system would add up to 450-500w. Under load, not during boot. It should work with the CX550F. Maybe it is a problem with the pcie splitters (which I wouldn't recommend using anyway).

 

2 hours ago, rodewouw_ said:

my current r9 setup works fine with any other power supply, in this case an old TX750 that I had lying around...

Just use the TX750 then? I'm assuming a crossfire R9 270x setup isn't going to be a permanent thing since nothing supports crossfire these days and a pair of R9 270x's in crossfire is going to perform worse than a modern mid range card anyway.

[rodewouw_]

With 'the psu' i'm referring to the CX550
v

So I did some testing this morning and found that the splitters work like expected in another pc, with the psu. When I powered the pc up for the first time with the TX750 it did prompt me with a "Post failure" and "Bios configuration error" even though the bios (modified or stock) works just fine with two other psus and this psu works fine in any other pc (?????)

When connecting the psu my motherboard does not seem to get power. At all.

 

Weird

[leclod]

7 hours ago, Spotty said:

R9 270x is only 180W TDP.

Sorry, I missed the "Total System Power Consumption"

[rodewouw_]

Solution: I have found it

 

Tye culprit might've been my AC240 wall power splitter to eight different outlets. The poor thing exploded on the inside and stopped working. When testing my main system I worked on it in my room where the outlet died, while testing with the TX750 happened in another room. I do beleive that some damage had been caused to my motherboard, since oc seems less stable (?????)