Ah, you've added some new info, which causes me to think there's a better way here. But before proceeding, let me make sure I got all the facts right.
A. You have a Corsair H60 CPU cooler system. It has a PUMP unit mounted on the CPU, and that has a cable with THREE wires that you have plugged into the mobo CPU_FAN header. Then that system has its rad and fan, now mounted on the back of your case to blow air out. For the FAN on that rad, it has a cable with FOUR wires, and you have it plugged into the mobo CHA_FAN1 header.
B. Your mobo also has a SECOND chassis fan header, CHA_FAN2, and there you had just the one Silentwing PWM 4-pin fan plugged in. Recently you have added a third fan that has only 3 pins. Using a Splitter, it now shares the CHA_FAN2 header with the Silentwing unit, and you are setting the CHA_FAN 2 header to DC Mode.
IF that is ALL correct, then I suggest you change all the connections, and some of this may sound odd, but I will explain why it works better. HOWEVER, if ANYTHING above I have misunderstood, do not make any changes until you tell me what I got wrong!
We'll start with the whys and then get into details. With the H60 system, the design concept is that the PUMP should run full speed all the time, and control of the CPU internal temperature is done by changing only the speed of the FAN on the radiator. Now, the CPU_FAN header is unique in this way: it does its automatic control of its fan according to a temperature probe built into the CPU chip itself; hence, THIS is the header that REALLY should be used to control the speed of the RAD fan. But of course, the pump is already connected to this header. A further consideration: the CPU_FAN header pays close attention to the SPEED of its "fan" and will warn you rapidly (may even take some drastic action) if it FAILS (i.e., no speed). With any AIO cooler system, the critical component that MUST work is the PUMP, so you want to have the pump connected to the CPU_FAN header in such a way that is speed is fed there.
Case ventilation fans, on the other hand, should be connected to CHA_FAN headers because those use a different temperature sensor built into the motherboard. That also is why those headers are NOT good for the fan that cools the CPU chip. CHA_FAN headers usually also monitor their fan's speed signal for failure and will warn you in that event, but not take drastic actions. You appear to have two CHA_FAN headers, and two DIFFERENT fan types for case fans.
Now for the details.
- Disconnect all those fans and the pump. Move the Splitter to the CPU_FAN header. Look very closely at the two male (with pins) outputs of the Splitter, and you will see that one has all 4 of its pins, and the other has only three, with Pin #3 missing. Plug the PUMP unit into the output with all four pins, and the RAD FAN into the other. This will put both items under automatic speed control by the CPU_FAN header based on the internal temperature sensor in the CPU chip. BUT the PUMP will make use of a "quirk" in the design of the two different fan systems. When you mis-match and plug a 3-pin device (the pump) into a 4-pin header that IS using the new PWM Mode, it receives from Pin #2 a full 12 VDC supply constantly and does NOT receive (nor could it use) the PWM speed control signal from Pin #4. So it always runs full speed, just as it was designed to do. Meanwhile the 4-pin fan on the other output of the Splitter DOES get that PWM signal and its speed IS controlled. NOTE that, to make sure this works, you MUST go into BIOS Setup for the CPU_FAN header and set it to use that PWM Mode - NOT DC Mode, and NOT "automatic" self-tuning if that is an option. Also note that, because you connect the PUMP to the Splitter output with all its 4 pins, the PUMP is the unit that will send its speed signal back to the CPU_FAN header for FAILURE monitoring. Of course, that also means that, whenever you look at the BIOS read-out for CPU Fan speed, it really will be the PUMP that is always running full speed, and you will never see the speed of the fan on the Rad.
- Now, connect the Silentwing 4-pin fan to the CHA_FAN1 header and ensure that its configuration is set to PWM Mode (ideal for this fan).
- Connect the new 3-pin fan to the CHA_FAN2 header, and configure it to use DC Mode.
- As far as the temperature control strategy or "Profile" for the two CHA_FAN headers, make then the same so those two fans will do essentially the same thing. Because they are different models, their speeds will NOT match generally, but they will perform very much alike.