I am trying to confirm if the ROG Strix OC Gaming 2x 90mm Fan (cooler design).
This using at performance Bios mode approximately 950 ~ 1000 rpm as lower at idle.
The 90 mm DC fan specifications :
2600 rpm at 13.8V
1800 rpm when this working with ASUS cards
70 Celsius max operating temperature.
Therefore please check your ASUS software utility and add your feedback.
Thanks.