According to a couple of report, it appears that Nvidia's Geforce GTX 1080 Founders Edition might be plagued by a rather weird fan issue.
Spotted at Geforce, EVGA and HardForum, the fan on the GTX 1080 Founders Edition suddenly spikes by increasing the fan speed by over 1000 RPM and then decline to normal value, producing repetitive and loud noise that is quite annoying.
The fan speed does not seem to be affected by the GPU temperature and it appears that the fan speed change is not even detected via software.
For now, it appears that the issue can be fixed by using the MSI Afterburner or EVGA Precision software and setting a custom GPU fan profile.
Hopefully this is just a minor issue that Nvidia will manage to fix with future driver update but for now, there is no update from Nvidia.
Source:
Overclock3D.net.