I have been having this issue with my power supply (650W EVGA G2 SuperNOVA) where there would be a crackling sound coming from it when my GPU (EVGA GTX 1080 Ti SC2) is under high load, for example the crackling sound always happens in 3DMark TimeSpy. I have tried the PSU and GPU in two different systems and had the same result, one system had an I7-6700k and an ASUS Z170K motherboard, the other system had an FX-6300 with and ASUS M5A97 R2.0 motherboard. I also tried using the GPU with a 550W EVGA G2 SuperNOVA in the I7 system and there was no crackling. Furthermore I have tried swapping the cables between the 550W G2 and the 650W G2 and there was still crackling coming from the PSU.
I have been dealing with this issue for months with EVGA (who have become increasingly unresponsive) and I have already gone through two RMAs, one with a replacement PSU and the other with a replacement GPU, neither RMA resolved the issue and I ended up returning the replacement PSU back to EVGA. EVGA do not know what the issue is and I do not want to go through a third RMA and have to pay for shipping again (I have already spent £30 on shipping, which is nearly half the cost of the power supply, that is money with which I could have got something like a 650W P2 or something else), I also do not want to have to risk getting a worse product with a third RMA as EVGA have said that they will give a different model of power supply, which may be a GQ or G3.
I will add a video shortly, but I would be grateful if anyone has any advice on this issue.