EVGATech_LeeMNVIDIA recommends - as do we - to use two separate power cables for the 3080s.
TunatronI'm seeing the same issue on the XC3 Ultra. The reason you're hearing it intermittently is because the fans stop when not under load, which stops the sound.
blackgoldI've heard buzzing from my computer when I hooked it up to a bad power inverter that was putting out 150 volts. It worked fine but it was so loud people heard it through my mic! "Check your mic cable" Bro it's not the mic XD XD XD It was also a grounding issue as well, as the inverter wasn't wired correctly. I guess my point is, it's fairly normal for a power supply to whine when it's working hard. So depending on the load and how you wire it, you can get different amounts of noise. Maybe create your own fan profile to test to fan noise. Some fans can create some funky noises when they spin down real slow, and increasing the minimum speed should avoid this. I use noise canceling headphones myself :D Edit: Maybe with the case off go sticking your ears around/directly on suspect components to try to find out what's making the noise
joeeohTunatronI'm seeing the same issue on the XC3 Ultra. The reason you're hearing it intermittently is because the fans stop when not under load, which stops the sound. Actually it's constant for me as soon as I hit the power button and does not change whether under load or not. Pitch also stays the same. Also tried monitoring correlation of fans with noise in Precision X1 and there doesn't seem to be any relationship. I'd link a video if I could but the forum seems to remove it automatically.
K1macSo After trying, I've realized it's just the fan near the front end (Under the "3080" portion of the graphics card) I've disabled this fan for now and seems to be working with NO WHINE. However, this isn't a real fix. I'm hoping EVGA Can help as I've clearly been able to identify the cause of it through minimal investigation, even just sending me a new fan would be appropriate at this point.