SPECS from Oldie but still Goldie:
Phenom II 1100T BE
Sapphire Radeon Fury R9 Nitro
ASUS M4A89GTD PRO-USB3
Mushkin Radioactive 2400 16GB 2x8GB (being run at 1600)
PNY 240 SSD
Seagate 1TB 7200 HDD
Hitachi 4TB 5400 HDD
I've been using the XFX PRO 650 PSU for maybe 7, 8 years, and it has served me well so far. However, and recently, when gaming or watching anime with madVR and upscaling, a horrible, buzzing-like noise, is produced from inside the PC. While it only happens with madVR, and some intensive games, and most of it seems to be coming from my GPU, I also suspect it might be my PSU on the way out (considering I've been having strange full-freeze locks lately).
On the other hand, a couple of years ago, I bought a used Corsair RM750i from /r/hardwareswap, Reddit, It was a unit meant for a used upgrade to a 8350 system to hold on until Ryzen launched. While everything seemed fine when I received the package, I learned the not-so-hard-this-time-way you can't really trust second-hand sellers, and found out the SATA cables delivered with the PSU were meant to be used with a different Corsair PSU. I installed this PSU in the system above, and, fortunately, something clicked, and some protections kicked in as soon as I turned on the PC (and my SSD and HDDs were spared). After a lot of troubleshooting, finally found out the foreign cables were the culprits, and ordered replacement cables, which actually work as they should (or, at least, don't kick any protections). Since then, I've never considered installing the PSU again, until now.
So now, here I am, with a maybe-failing PSU, and one which actually spared me and my components before. I have tested the Corsair PSU with a multimeter, and so far (and without load), the voltage values for each output are correct. However, I'm not completely confident I should exchange the XFX PSU now, or wait until it fails before I take the risk. I'm also worried the Corsair PSU might have sustained damage from the bad cables (even considering the protections kicked in in time), but it might not be the case.
What would you suggest in this particular situation? Anything else I could try/do to reduce the risk to my build before swapping the PSUs?