Ok here's the deal. I recently put an old HD7950 into my son's PC. Because it's a weak card relative to the CPU (Ryzen 1600) I decided to overclock it and bumped up the core yesterday from 800 to 950. I haven't previously overclocked this GPU in this system. My son played a bit yesterday and apparently left the game running when he finished. I went to turn on the machine today and to my surprise it was completely dead. No beeps, no lights, no fans, no nothing. I tried removing all the devices including GPU to reduce power consumption, still dead. Interestingly after I tried another power lead, when I flipped the psu switch back on, it let out a brief flash/spark at the back of the PSU. To be fair I've seen this once or twice in the past from other PSUs without any issues arising. I know that the 7950 is a power-hungry card (1x8pin 1x6pin) so when overclocked I assume it draws even more power, even though I didn't touch the voltage yet. The PSU is a OCZ Powerstream 470W, about 15 years old although it's only had light usage for the past 10 years or so (not in my main rig). It doesn't have any PCI-E connectors so I have it rigged up with with molex adapters and also only has 2x SATA power so again I have 1 adapter for the 3rd SATA drive. Basically it's a bit Heath Robinson, but never had any issues when it was running an RX480 (single 6pin power). I tried the PSU in another machine that works fine with a weaker PSU, completely dead. So I'm fairly sure the PSU is knackered. What I don't yet know is whether any other components are damaged, as I don't really want to tear down my main PC to put the PSU from that in it. So I've got a replacement PSU coming tomorrow, the OCZ whilst a pretty decent unit for its time was probably due replacement anyway for something a bit more modern. The one piece of the puzzle I'm unsure about is whether the GPU overclock was the cause or just a co-incidence. Has anyone seen something similar?