What is the Make & Model of your AMD 6800XT GPU Card?
Also do you have all the GPU Power cables connected from the PSU to the GPU Card?
Generally the fans won't start to spin until it reaches a certain temperature. Then I believe all the 3 fans should start running at the same time.
Possibly the manufacturer of your GPU card has it programmed to work with one fan only until it reaches a higher temperature then all 3 starts. but generally all fans on the GPU card should start at the same time.
But if your GPU temperatures are above, let say 80C, then all 3 fans should be spinning. if not then you have a problem with your GPU Card.
Could also be a power issue with your PSU.
This Tech site gives some good information in what can cause a GPU fan not to spin: https://techguided.com/gpu-fan-not-spinning/
