Question Possible PSU issue after trying cheap extension cables.

[Anthro]

Hi Folks,
I've been running this system for about a month with no issues until I tried adding extension cables to my graphics card.
My system is: Windows 11
M/B ; MSI MAG Z790 Edge WIFI (DDR5)
CPU: Intel 13700k
RAM: 64 GB Kingston Fury Beast
PSU: Corsair RM1000i
GFX Card: XFX RX 7900 XTX

The PSU was second hand and came with it's own set of custom cables that were a silvery white and very thin (slightly under 2mm) but were rated for that PSU and only that PSU I was told by the person selling it to me.
I purchased a set of EZDIY-FAB extension cables and extended them, just for the GFX card to tidy up my build a bit.
I loaded windows 11 successfully after that and went into Adrenaline software to check voltages and everything looked happy initially. I did notice the screen was occasionally glitching for like a few milliseconds so I thought I'd use the Adrenaline built in stress test. As soon as I clicked on it and confirmed the 1 minute run time, the screen went black and locked up. Only way out was to press and hold the power button for 4 secs to turn off the machine.
I guess installing the extensions have not worked well with my combination of custom cables so I'm trying to work out what I've fried.
The GFX card or the PSU?
I can install and old GFX card Strix 970 ti and that will be recognised and boot (after a lot of faffing around with clearing CMOS etc) but that doesn't confirm the issue 100%. That only uses x2 8 Pin power connectors whereas the 7900 XTX uses x3 8 Pin power connectors.
Is it possible that the PSU is now damaged and can no longer supply x3 8 Pin connectors or is it more likely a fried graphics card?

I'm currently using the same PC now using the iGPU but if I install the 7900 XTX and power it up, I get the white VGA LED on the motherboard indicating an issue. I have to disconnect the x3 8 Pin power cables from the GPU before the iGPU is usable again.

Also to note; when the 7900 is plugged into the PCIe socket, if the power cables are unplugged there is a red led above the card power socket for each of the x3 connectors but if you plug them in, the lights go out (presumable indicating that it is receiving power)

 

[Aeacus]

and came with it's own set of custom cables that were a silvery white and very thin (slightly under 2mm) but were rated for that PSU and only that PSU I was told by the person selling it to me.

Do you have this exact PSU with these exact cables? ->

I purchased a set of EZDIY-FAB extension cables and extended them

Bad idea. For the very least, extending power cables increases the ripple in power delivery. And for the worst, it can lead to cable melt/catching fire. Also, never use 3rd party hardware without confirming with Corsair 1st.

For example, i'm running Seasonic PRIME TX-650 and before i bought custom sleeved power cables for it, i contacted Seasonic and asked if the CableMod set that i was planning to buy, is good enough for the PSU + if i use those custom sleeved cables, would my warranty be voided. Seasonic rep was nice and replied that CableMod cables are of high quality, equal to Seasonic's own, in-house power cables (that they ship with PSUs) and i'm fine using CableMod cables with my Seasonic unit. Also, no warranty is voided when using CableMod custom sleeved power cables.

This, above, is how you should've done prior to buying your "easy, do-it-yourself, fabricator" (EZDIY-FAB) cables.

At current moment, and based on symptoms, your GPU is toast. Also, you can not contact Corsair either and blame them, since you screwed up.
Moreover:

The PSU was second hand

Why did you get used PSU? 🙄
You clearly have enough money to buy good quality brand new PSU.

At this point, open up your wallet and buy new PSU as well. Brand new this time, with warranty.

 

[Anthro]

Do you have this exact PSU with these exact cables? ->

Bad idea. For the very least, extending power cables increases the ripple in power delivery. And for the worst, it can lead to cable melt/catching fire. Also, never use 3rd party hardware without confirming with Corsair 1st.

For example, i'm running Seasonic PRIME TX-650 and before i bought custom sleeved power cables for it, i contacted Seasonic and asked if the CableMod set that i was planning to buy, is good enough for the PSU + if i use those custom sleeved cables, would my warranty be voided. Seasonic rep was nice and replied that CableMod cables are of high quality, equal to Seasonic's own, in-house power cables (that they ship with PSUs) and i'm fine using CableMod cables with my Seasonic unit. Also, no warranty is voided when using CableMod custom sleeved power cables.

This, above, is how you should've done prior to buying your "easy, do-it-yourself, fabricator" (EZDIY-FAB) cables.

At current moment, and based on symptoms, your GPU is toast. Also, you can not contact Corsair either and blame them, since you screwed up.
Moreover:

Why did you get used PSU? 🙄
You clearly have enough money to buy good quality brand new PSU.

At this point, open up your wallet and buy new PSU as well. Brand new this time, with warranty.

The PSU is black and the cables aren't the same as in the picture you posted. They are very thin. Slightly less than 2mm. Those in the pic I would guess are closer to 4mm.
They've been working solidly for a month on their own.
I'm not looking to blame anyone else here really. Was just seeking advice on the symptoms to narrow it down further and hoping it's just the PSU or potentially just the PSU which is cheaper to replace.
As for buying second hand. It's a bit beyond the scope of my post but that was the first part I bought before deciding on a completely new system so it was something I already had. I've bought them before second hand and I've sold components on eBay over the years. As for having enough money, well I'm paying on finance over 12 months for most of my system excl. the Gfx card.
Thanks

 

[Aeacus]

The PSU is black and the cables aren't the same as in the picture you posted. They are very thin. Slightly less than 2mm.

If so, then the cables with PSU are not original and any damage to system is as good as given. Unless you can identify those custom sleeved power cables.

You could ask from the person who sold you that RM1000i with questionable cables, if they are willing to reimburse you with your losses, but i doubt they do it.

Was just seeking advice on the symptoms to narrow it down further and hoping it's just the PSU or potentially just the PSU which is cheaper to replace.

Well, you did test with 2nd GPU. And since 2nd GPU (Nvidia) works, but original one doesn't, your GPU (Radeon) is toast.

As for buying second hand. It's a bit beyond the scope of my post but that was the first part I bought before deciding on a completely new system so it was something I already had. I've bought them before second hand and I've sold components on eBay over the years.

Some PC components are fine to be bought used. E.g CPU, RAM, PC case, fans. Others are not, e.g disk drives, GPUs. Especially PSUs. Never buy an used PSU.
Thus far, you've gotten lucky by buying cheap used components and haven't had much of an issue. But your luck did run out and now, you're looking to fork out even more money.

As for having enough money, well I'm paying on finance over 12 months for most of my system excl. the Gfx card.

Your Radeon GPU is easy 1000 bucks GPU. And like i said, if you have money to buy 1000 bucks GPU, you'll also have money to buy proper, brand new PSU.
E.g any of these fine numbers, pcpp: https://pcpartpicker.com/products/compare/rt848d,fKhmP6,XBVmP6/

So, at current moment, your 1000 bucks Radeon GPU is toast since you cheaped out on your PSU.
No matter how i look at it, the savings made on RM1000i, compared to brand new PSU, do not come even close to the price of new GPU and new PSU. So, do you still think it's good idea to buy used PSU?

 

[Anthro]

Yes. It's been working great as cheap as it was.