"closed air rig" is the problem.

Usually, 1050ti*12 is without any problem at opened air rig, 1050ti's fan is enough for cooling itself.

But at closed air rig, you need lots of additional powerful fan to send cooler air to the GPUs, generating noise.

However, you have buy it, so give it more fans and enjoy the noise.
Or you can ignore the temperature less than 70 degrees Celsius.