I don't know how to connect my case fans

[HumanBull]

I have a NZXT S340 Matte Black/Red Steel ATX Mid Tower Case, and a MSI Gaming B150 Gaming M3 LGA 1151 Intel B150 HDMI SATA 6Gb/s USB 3.1 ATX Intel Motherboard, along with a CORSAIR CX Series CX600 600W 80 PLUS BRONZE Active PFC ATX12V & EPS12V Power Supply. I don't know what to connect my case fans to what. I'm not sure what to connect it with, but I do know is that I have either a 3 or 4 pin molex connector from either the case or power supply. I'm not so sure what to connect to what.

 

[krzyimprt]

I have a NZXT S340 Matte Black/Red Steel ATX Mid Tower Case, and a MSI Gaming B150 Gaming M3 LGA 1151 Intel B150 HDMI SATA 6Gb/s USB 3.1 ATX Intel Motherboard, along with a CORSAIR CX Series CX600 600W 80 PLUS BRONZE Active PFC ATX12V & EPS12V Power Supply. I don't know what to connect my case fans to what. I'm not sure what to connect it with, but I do know is that I have either a 3 or 4 pin molex connector from either the case or power supply. I'm not so sure what to connect to what.

Looking at your motherboard you have the following connectors.

2 x 4-pin CPU fan connectors
3 x 4-pin system fan connectors

 

[corroded]

did you look in the manual? Pages 26 and 27 tell you where the fan headers are on the MoBo

 

[raisonjohn]

Your motherboard should have a total of five fan headers: 1) CPUFAN1 at the top beside the RAM slots; 2) CPUFAN2 at the top far right edge of the motherboard; 3) SYSFAN1 below the cpu and above the M.2 and topmost PCIe slot; 4) SYSFAN2 along the bottom left edge of the motherboard; and 5) SYSFAN3 at the top right edge of the board just below the cpufan2.

Note that both CPUFAN1 and CPUFAN2 are PWM-Mode fan connectors which allows you to control the fan's rpm/speed based on a signal and temperature reading while providing constant 12VDC output to the fans (as long as these fans are also PWM, 4-pin fans). On the other hand, the SYSFAN1-3 are all Voltage-Mode fan connectors which only allows the fan's rpm/speed to be changed by lowering the DC voltage supplied (only the 3 pins of the SYSFAN headers have a connection, the 4th has none).

If you want to plug in your case fans (you did not mention how many these are) into the motherboard headers, you have these 5 fan headers to choose where to plug your fans into (note that this includes your actual CPU fan/cooler).

You can also plug in the case fans directly into the PSU via a 3pin/4pin-to-Molex adapter. This is synonymous to plugging the fans in the SYSFAN headers (using 12VDC power) but you won't be able to change their speed and it will run 100% all the time.

 

[Paperdoc]

In my opinion, the best way to connect and control fans is always to use the mobo fan headers and allow the mobo to control the fans automatically, according to the temperatures measured by sensors. There are two such system that operate separately. One is for cooling the CPU, and your mobo has two headers available for that - CPUFAN1 and 2 - that are the same. So you can use either of them for your CPU cooler (both if you have an unusual setup). The second is for case ventilation, and your mobo has three headers for that, SYSFAN1, 2 and 3. These are guided by a temperature sensor on the mobo, rather than one inside the CPU chip. All three of these are the same, so you can easily use each for a fan. (If you have more fans, that can be arranged, too.)

Your case comes with two (I think) fans pre-installed each with a standard 3-pin connector on the end of its wires. That means they must be connected to a mobo header that uses Voltage Control Mode, and fortunately that is exactly what you SYSFANn headers do. Those mobo headers have 4 pins sticking up, but don't worry. You will find the fan connectors fit onto those headers only one way, leaving Pin #4 bare, and that is exactly what you want. When you do things this way, the speeds of all your fans will be adjusted continuously and automatically by the mobo according the the cooling needs of the CPU and mobo components.