Well, that's the only way to access the speed control of those fan headers. Otherwise you will have you live with whatever the default speed is.
Snoop around in the BIOS. IF you exit without saving, you'll do no harm. When you find the sys fan section I pointed you to and you feel comfortable, make a change to just the one header you are plugged into. Save and exit. That's all that you will have altered.
Did you find the pages I mentioned?