No harm it may shorten their lifespan some, not enough to matter. If you want the system to run cooler. I would use a more aggressive fan speed curve rather than a constant speed. I assume the issue is that the GPU is not getting enough airflow. An aggressive system fan curve would fix this. That's what I did. So, that it is quiet during regular use but the system fans ramp up when gaming. To give my GPU plenty of air.