Unlike other case fans, the one in the rear isn't optional.
The case has two fans sucking air in from the front, they blow straight through to the CPU fan which blows onto a rear fan blowing out. There are two SSDs attached to the left-most drive mounting ...
Most BIOS settings you don't need to change. This isn't one of those.
The computer fan in your desktop PC or laptop is there to keep things cool and running smoothly. However, if you can barely hear yourself think over the cacophony of noise emanating from your computer ...