Hello, I have a gigabyte GA-965P-DS4 motherboard, with Intel Core 2 Duo E6600 CPU and the stock fan of intel that came in the box with the CPU. The fan is connected with 4 wires to the motherboard. The fan sometimes stops rotating, and sometimes it'll be in a state where it rotates for a second, then stops a second, then rotates a second again, and so on for a long while. Especially that last thing worries me. What worries me more is that, if the fan is doing that, when I touch the wires of the fan, the fan suddenly rotates continiously, as if there's a bad contact in one of the cables that gets fixed for a while if I move the cables a bit. Does the motherboard CPU combination I mentioned, automatically control fan speed depending on the temperature of the CPU? If that is so, can it happen that when it's at a border between hot and cold, it'll go in this state where the fan starts/stops spinning every second? Does anyone know what the function of the blue, black, yellow and green wire of the fan are? Thanks.

There was a setting for smart control on the motherboard, and when turning it off the fan constantly turns at full speed.

This proves that it's not a bad contact, and I set it to smart control again to make it less noisy :)