Lets' start with the differences between 3- and 4-pin fans. BOTH can have their speed controlled, but that requires different methods. For a 3-pin fan, the signals on the mobo header pins and the standard fan wire colours are: Pin #1 - BLACK - Ground Pin#2 - RED - +VDC power ranging from 12 VDC max speed down to 5 VDC - less may allow the fan to stall Pin #3 - YELLOW - Fan Speed - a series of 2 pulses per revolution sent by the fan motor back to the mobo header for counting. Regardless of how the mobo header decides what the fan speed should be, the mobo accomplishes control of the fan speed by varying the voltage sent out on pin #3. That is called Voltage Control Mode (aka DC Mode) of fan speed. For a 4-pin fan the wire colours are different; the electrical signals are similar in most cases but the differences are important. Pin #1 - Ground Pin#2 - +VDC power constantly 12 VDC Pin #3 - Fan Speed - a series of 2 pulses per revolution sent by the fan motor back to the mobo header for counting. Pin #4 - PWM (Pulse Width Modulation) signal. This is a signal in the 20kHz frequency range that is similar to a classic Square Wave in that it is either fully on or fully off. What is special, though, is that the time the wave is "On" is NOT always 50% as it is in a square wave. The "%On" value can be changed. Inside the motor case there is a small chip that uses this signal to switch the power from the 12 VDC line to the motor windings on and off VERY rapidly, effectively changing the average time the motor gets power, and hence altering its speed. (By the way, this is not how industrial motor PWM speed controls operate, but that is irrelevant here.) The mobo controls the speed of the fan by varying the PWM signal sent out on Pin #4. That is called PWM Mode of speed control. On a mobo, any 3-pin fan header can only use the older Voltage Control Mode, since it cannot send out a PWM signal with no Pin #4. Today almost all fan headers on mobos have 4 pins and CAN do PWM Mode. BUT they also CAN do the older Voltage Control Mode simply by not sending out any signal on Pin #4 and varying the Voltage on Pin #2. In the configuration options of most mobo header you are given a choice of which Mode this header will use, and that ought to be set according the the type of fan you have plugged into it. If you make the header signal Mode match the fan type (3-pin or 4-pin), the fan motor's speed WILL be controlled. When you connect more than one fan to a single header (or one port of the Smart Device you have), all of them receives the same signals and does exactly the same thing.. As I said above, one small note is that the header cannot deal with pulse signals for speed coming at it from more than one fan, so the cables from that port to each fan are set up with Pin #3 available on ONLY one output connector. That has no effect on fan speed. It does impact ability of a fan header to detect FAILURE of a fan from lack of a speed signal when SOME of the fans never report their speed. If I understand correctly, you have added extra fans merely by plugging them each into the outputs of a daisy-chaing connector system on each of the original fans supplied with the case. I would presume that the way the original fans are wired is that each fo those sends its own speed back to the source (port on the Smart Device) but does NOT send back the speed of any fan plugged into its daisy-chain output. So what CAM can show you is the speed of the three original fans plugged into the Smart Device's three ports, but not of an others. Answer from Paperdoc on forums.tomshardware.com