The Gigabyte GA-Z77X-D3H Z77 board has several "fan" slots, above and beyond the "cpu_fan." These look like they have a small 4 pin input, but all my case fans (and other fans I have) have a 3 pin input. What exactly are these slots on the board for? Are they not for case fans, and am I misunderstanding? Or do I just not have the right kind of fans?
Both the motherboard and the fan cable should be labeled. The 4th pin gives you a feature that automatically adjusts your fans' speeds according to the computer's workload (more work for the computer = more fan speed), but the fans will still work just fine without this additional feature.