TechPowerUp posted a review on the MSI GTX 1080 Gaming X 8 GB
A quote from the article:
MSI's GTX 1080 Gaming X is an overclocked, custom-design variant of the GTX 1080, which doesn't throttle and comes with almost inaudible fans (in heavy gaming), and zero-noise in idle and light gaming, because the fans are switched off while the card is running cool.MSI GTX 1080 Gaming X 8 GB @ techPowerUp