Modular PSU cables never go in the big box. They go back in the PSU box if I'm being smart. Then I know which PSU they came from and can throw them out in ten years along with the PSU itself.

(I'm rarely smart and have a second big box of modular PSU cables that I maybe ought to get rid of.)

They aren't even consistent within manufacturer!

They're standardized on the device side, but not the PSU side. So always check pinout before you make the very reasonable assumption that if it fits it works

A PSU cable tester is valuable for this. They're much cheaper than a replacement PSU, and you can plug in cables wherever they fit on a PSU, and test whether the output is correct for the CPU/PCI/motherboard/SATA connector you want to plug it into. The PSU and cable might be a black box, but the output is always testable.

That's an expensive mistake to make, though frying your HDDs is usually a lot cheaper than frying your GPU.

It's seriously annoying that this is the case though. Unless you kept the cables in the original package or in a labelled container, you cannot safely use them again if you owned more than one modular PSU.

Before you fry a whole 12bay drive array and backplane let me tell you this:

6 pin EPS and 6 pin PCIe power cables are not the same. Even though the connector may fit they are not the same pinout.

I too have been burned by the BBOC, although not as badly as this:

I picked out a random short ethernet cable that looked nice (it was flat) to connect my wifi AP to my router.

It took me about a month to realize my 100mbit internet connection had dropped down to about ~85-90mbit, but more importantly, transferring files between a wifi client and the wired network was also only ~90mbit.

Turned out the cable was so bad that it only connected at 100mbit...

I have now gone the other way and I actually curate the BBOC: All cables I get for 'free' with random appliances now go straight to the bin (unless they are specialised) and I only keep cables I specifically bought and know they adhere to a standard.

I had the same thing happen to me when I plugged in my massager charger into the blood pressure monitor and fried it

Oh for crying out loud, I've spent my life believing if it fits it's right. %$@&#!