The BIOS fan control on this board is actually pretty lacking. You can have it automatically control the CPU and/or system fan, but the CPU fan ramps up way more aggressively than is necessary IMO. And unfortunately Gigabyte doesn't provide different profiles to choose from for the CPU fan speed control (for example, you could select either "quiet" or "performance" modes, where "performance" would obviously ramp up faster but cool better; even my four year old ASRock budget board had this option). There's no setting for target temperature like on ASUS, MSI, and a lot of other boards. I'm actually very disappointed in this aspect of the board, it's seriously lacking.
System fan, however, doesn't ramp up very quickly, so I just have a passive CPU cooler and then let the motherboard automatically control the case fans (I bought two of those Arctic Cooling 120mm fans that allow you to split PWM, so they're both run from the system fan header). At idle they spin at 300-400RPM, and at load 500-600RPM. This is about perfect for my system, provides adequate cooling and is very, very quiet.
Or if you want to control speed yourself, SpeedFan should work with this board. This post explains how to set SpeedFan up so you can switch control from the BIOS to software.
http://www.silentpcreview.com/forums/vi ... ht=#504019