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Trying to connect as many case fans to my motherboard as possible

I plan on getting 7 x 140mm, 6 x 120mm PWM fans

PSU

http://www.bequiet.com/en/powersupply/611

Motherboard

https://us.msi.com/Motherboard/B250M-GAMING-PRO.html#productFeature-section

Internal I/O Connectors

- 1 x 24-pin ATX main power connector
- 1 x 8-pin ATX 12V power connector
- 6 x SATA 6Gb/s connectors
- 2 x USB 2.0 connectors (supports additional 4 USB 2.0 ports)
- 1 x USB 3.1 Gen1 connector (supports additional 2 USB 3.1 Gen1 ports)
- 1 x 4-pin CPU fan connector
- 2 x 4-pin system fan connectors
- 1 x Front panel audio connector
- 2 x Front panel connectors
- 1 x TPM module connector
- 1 x Chassis Intrusion connector
- 1 x Serial port connector
- 1 x Parallel port connector
- 1 x RGB LED connecotr
- 1 x Clear CMOS jumper
Reply to Ramonjrfer
6 answers Last reply Best Answer
More about connect case fans motherboard
  1. Great, thanks for letting us know.
    Reply to Nine Layer Nige
  2. I would really wonder why 13 fans. More is not alwats better and for your average PC like your building, no overclocking, single video card, from the board your using 3 fans would work fine for anything you can build with that.
    Reply to Zerk2012
  3. Best answer
    Leaving aside the why's of all those fans, there is only one way to do this. In doing it, you will need to check that a few factors and a limit are OK for you.

    You do not tell us about your CPU cooling system. I'm going to assume those 13 fans you listed all are for case ventilation, and that the CPU cooling system is additional. That can have an impact on the power limit.

    The factor that limits this a single-solution story is that the mobo has only ONE fan header that actually uses PWM Mode for control, and that's the CPU_FAN header. The mobo's two SYS_FAN headers use only Voltage Control Mode. To power and control all those fans you will need to use a 4-pin PWM fan HUB. This is a device that gets power for all its fans directly from a SATA power output from the PSU, thus avoiding the 1.0 amp limit of a mobo fan header. However, even that has a limit - a SATA power output can supply up to 4.5 amps total, which works out to about 0.3 amps per fan for 15 fans max. That's OK as long as the fans you plan all are "normal" ones, which typically use 0.1 to 0.25 amps each. BUT you need to check three important possible items here:
    (a) What is the total current draw for your CPU cooling system? If it is a liquid-cooled system, or IF it uses many fans, this could raise that particular system's current requirements.
    (b) If any of those fans also have LED's in them, that is a real problem. Typical LED fans pull 0.4 to 0.5 amps each, about twice as much as "normal" ones.
    (c) Are you using any special "high power" fans? Check the specs on all your fans AND on the CPU cooling system, and add them all up to be sure of the total fan power requirement.

    Here's an example of a good 4-pin fan Hub

    https://www.newegg.com/Product/Product.aspx?Item=9SIAABJ4SF8917&cm_re=fan_hub-_-11-999-309-_-Product

    Note that it has two cables coming out of it. One goes to a SATA power output from the PSU. The other goes to a mobo fan header that MUST be one using PWM Control for fans. In your case, that can only be the CPU_FAN header. This cable also returns to the mobo the speed signal of ONLY one of the fans plugged into the Hub - in particular, only the fan connected to its Port #1 which is identified by special markings. For you it is IMPORTANT that you connect to that Hub port the CPU cooler. The mobo CPU_FAN header uses extra care in checking the cooler for the CPU to be sure it never can allow overheating, so it is essential that the fan signal it receives from the Hub must be the fan that actually is cooling the CPU.

    This Hub has eight 4-pin fan ports. Seven of these are NOT the CPU cooler, and those you need to power 13 case ventilation fans. Thus you will need a way to do this. One way is to use a bunch of Splitters that would let you connect two fans to each of the seven Hub ports. The other is to buy TWO such Hubs and "stack" them. For the first one, you plug its fan connector into the mobo CPU_FAN header as usual, and plug the actual CPU cooler into that Hub's Port #1. Then you plug into that Hubs' port #2 the fan connector from the second Hub, and connect its SATA power connector to another one from the PSU. On the second Hub it does not matter whether or not you plug something into its Port #1 because that speed signal will never be sent through the first hub's Port #2 to the mobo. This system gives you one connection for the CPU cooler on Port #1 of the first port, then six ports on that hub plus eight ports on the second hub for your case fans.

    Doing the two-Hub solution means consuming two SATA power outputs from the PSU, which might be a problem for you. But you probably will have more 4-pin Molex power outputs from that PSU than you need. So get one of these adapters that makes 2 SATA power output connectors from one 4-pin Molex output

    https://www.newegg.com/Product/Product.aspx?Item=N82E16812422777&cm_re=Molex_to_SATA_power_adapter-_-12-422-777-_-Product

    The 4-pin Molex output capacity is more that adequate to power all those fans.

    There are two facts you need to be aware of in all this. One is that the only mobo fan header you will use is the CPU_FAN header. Like all such headers, it can only handle a speed signal from ONE fan, so the Hubs are designed to ignore all the fan speed signals except the one from Port #1. Thus you will never see the actual speeds of ANY of your case ventilation fans. That means that, from time to time, YOU will need to inspect all those fans to verify that they are still working, and replace any that are stopped or that appear to be getting "stiff" from bearings wearing out. The other is that ALL fan speeds in this system will be under exactly the same control system, and that will be based on the temperature measured by a sensor inside the CPU chip. That is the sensor the CPU_FAN header uses to guide its control strategy. This does NOT mean that all the fans will run at the same speeds. It simply means that all the fans will receive the same control signals, and each fan will run at whatever speed that means for it. Most likely all the 120mm fans will appear to run at one speed, all the 140 mm units at another speed, and the CPU fan at its own speed.
    Reply to Paperdoc
  4. Paperdoc said:
    Leaving aside the why's of all those fans, there is only one way to do this. In doing it, you will need to check that a few factors and a limit are OK for you.

    You do not tell us about your CPU cooling system. I'm going to assume those 13 fans you listed all are for case ventilation, and that the CPU cooling system is additional. That can have an impact on the power limit.

    The factor that limits this a single-solution story is that the mobo has only ONE fan header that actually uses PWM Mode for control, and that's the CPU_FAN header. The mobo's two SYS_FAN headers use only Voltage Control Mode. To power and control all those fans you will need to use a 4-pin PWM fan HUB. This is a device that gets power for all its fans directly from a SATA power output from the PSU, thus avoiding the 1.0 amp limit of a mobo fan header. However, even that has a limit - a SATA power output can supply up to 4.5 amps total, which works out to about 0.3 amps per fan for 15 fans max. That's OK as long as the fans you plan all are "normal" ones, which typically use 0.1 to 0.25 amps each. BUT you need to check three important possible items here:
    (a) What is the total current draw for your CPU cooling system? If it is a liquid-cooled system, or IF it uses many fans, this could raise that particular system's current requirements.
    (b) If any of those fans also have LED's in them, that is a real problem. Typical LED fans pull 0.4 to 0.5 amps each, about twice as much as "normal" ones.
    (c) Are you using any special "high power" fans? Check the specs on all your fans AND on the CPU cooling system, and add them all up to be sure of the total fan power requirement.

    Here's an example of a good 4-pin fan Hub

    https://www.newegg.com/Product/Product.aspx?Item=9SIAABJ4SF8917&cm_re=fan_hub-_-11-999-309-_-Product

    Note that it has two cables coming out of it. One goes to a SATA power output from the PSU. The other goes to a mobo fan header that MUST be one using PWM Control for fans. In your case, that can only be the CPU_FAN header. This cable also returns to the mobo the speed signal of ONLY one of the fans plugged into the Hub - in particular, only the fan connected to its Port #1 which is identified by special markings. For you it is IMPORTANT that you connect to that Hub port the CPU cooler. The mobo CPU_FAN header uses extra care in checking the cooler for the CPU to be sure it never can allow overheating, so it is essential that the fan signal it receives from the Hub must be the fan that actually is cooling the CPU.

    This Hub has eight 4-pin fan ports. Seven of these are NOT the CPU cooler, and those you need to power 13 case ventilation fans. Thus you will need a way to do this. One way is to use a bunch of Splitters that would let you connect two fans to each of the seven Hub ports. The other is to buy TWO such Hubs and "stack" them. For the first one, you plug its fan connector into the mobo CPU_FAN header as usual, and plug the actual CPU cooler into that Hub's Port #1. Then you plug into that Hubs' port #2 the fan connector from the second Hub, and connect its SATA power connector to another one from the PSU. On the second Hub it does not matter whether or not you plug something into its Port #1 because that speed signal will never be sent through the first hub's Port #2 to the mobo. This system gives you one connection for the CPU cooler on Port #1 of the first port, then six ports on that hub plus eight ports on the second hub for your case fans.

    Doing the two-Hub solution means consuming two SATA power outputs from the PSU, which might be a problem for you. But you probably will have more 4-pin Molex power outputs from that PSU than you need. So get one of these adapters that makes 2 SATA power output connectors from one 4-pin Molex output

    https://www.newegg.com/Product/Product.aspx?Item=N82E16812422777&cm_re=Molex_to_SATA_power_adapter-_-12-422-777-_-Product

    The 4-pin Molex output capacity is more that adequate to power all those fans.

    There are two facts you need to be aware of in all this. One is that the only mobo fan header you will use is the CPU_FAN header. Like all such headers, it can only handle a speed signal from ONE fan, so the Hubs are designed to ignore all the fan speed signals except the one from Port #1. Thus you will never see the actual speeds of ANY of your case ventilation fans. That means that, from time to time, YOU will need to inspect all those fans to verify that they are still working, and replace any that are stopped or that appear to be getting "stiff" from bearings wearing out. The other is that ALL fan speeds in this system will be under exactly the same control system, and that will be based on the temperature measured by a sensor inside the CPU chip. That is the sensor the CPU_FAN header uses to guide its control strategy. This does NOT mean that all the fans will run at the same speeds. It simply means that all the fans will receive the same control signals, and each fan will run at whatever speed that means for it. Most likely all the 120mm fans will appear to run at one speed, all the 140 mm units at another speed, and the CPU fan at its own speed.


    Now that i know i wont be able to control them, I'll change to the models without pwm.
    (a) 326Volts without adding the fans
    (b) no leds
    (c) they also don't have any "high power" or anything like that.
    Electrical Specs
    120 fan
    Rated voltage DC (V)12
    Operating voltage DC (V)5 ~ 13.2
    Current consumption (A)0.12
    Safety current (A)0.12
    Input power (W)1.44
    140 fan
    Rated voltage DC (V)12
    Operating voltage DC (V)5 ~ 13.2
    Current consumption (A)0.06
    Safety current (A)0.3
    Input power (W)0.72

    This is my cpu fan
    https://www.newegg.com/Product/Product.aspx?Item=N82E16835103099&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
    Reply to Ramonjrfer
  5. Still funny to me for the price of 13 fans you could buy better parts.
    Reply to Zerk2012
  6. "Now that i know i wont be able to control them, I'll change to the models without pwm."

    NO, don't do that!

    You did not understand all that. There is a common misconception that 3-pin fans cannot be controlled, and 4-pin ones can. That is wrong. Both can be controlled, but the method is different. 3-pin fans require Voltage Control Mode, and 4-pin fans work best with PWM Mode control.

    First of all, the whole point of my recommendation was that this DOES control the speeds of all those fans. The only thing it does NOT do is show you what those speeds are! And ANY system using that many fans will have exactly that same limit of not showing you fan speeds.

    The only way to provide power AND do automatic mobo-based CONTROL of so many fans is to use Hubs that get power directly from the PSU, and not from a mobo header. BUT the only Hubs that can do that easily are PWM hubs that MUST use PWM fans! There is one Hub design I know of that can control 3-pin fans if given a PWM mobo header to use, but it has six ports on it and costs a few bucks more than the Silverstone one I suggested. To control 13 3-pin case fans plus a 4-pin CPU cooler you would need two of those Hubs plus at least two Splitters, so your costs would be higher there, offsetting savings between the 4-pin and 3-pin case fans.

    Thanks for posting the fan specs. Those ones have quite reasonable current needs and can work as I suggested.

    Thanks for Best Solution.
    Reply to Paperdoc
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