[SOLVED] How much fans can this motherboard support?

[zuhc]

Yeah so, I am planning to put 4 fans, 3 of which are the included fans from the case, they are transparent and they draw up to 0.16A

And the other one is a Deepcool RF120R (Red) This one draws 0.18A

I just wanna make sure if the motherboard has enough slots for all of my fans, if not I'll buy a splitter or something

 

[Wolfshadw]

Look for the number of SYS_FAN connection ports on the Motherboard Layout page of the motherboard manual, found on most support pages of motherboard manufacturer web sites.

-Wolf sends

 

[zuhc]

Look for the number of SYS_FAN connection ports on the Motherboard Layout page of the motherboard manual, found on most support pages of motherboard manufacturer web sites.

-Wolf sends

I mean, I do not have the manual because I haven't bought the PC yet?

 

[Paperdoc]

It would have helped if you had told us exactly which "this motherboard" is.

The Deepcool unit is a 3-pin design. Most fans included with cases also are 3-pin, so you should plan your connections assuming all 3-pin fans. That means two details to adhere to (see below). But for starters, check the mobo manual for a spec of the max current each fan header can supply. Most are 1.0 A max; a few are more, and I've seen some only 0.5 A. The four fans you specify total 0.66 A total, so for most mobo headers you CAN connect all four fans to a single header if you wish. Or, if you have more headers available, split them up into smaller groups.

For 3-pin fans you MUST use a SPLITTER to make groups - you cannot use a HUB. What's the difference? Do NOT rely on the name the seller gives! A SPLITTER is a simple device that has only two types or "arms" (if a group of cable arms) or connectors (if a small circuit board). There is ONE "arm" ending in a 4-pin female fan connector that must plug into a mobo fan header, either SYS_FAN or CHA_FAN. There are two ore more male (with pins) output "arms" or headers where you plug in your fans. The Splitter merely connects all of the fans in parallel to the Ground and +DCV lines from the header, so all of the power for the fans must come from the header and it is limited to that header's max current spec. Now, a mobo header can deal with the speed signal sent back to it from only ONE fan. So a Splitter will send back only one fan's speed signal and ignore the others. Often this is done by simply omitting Pin #3 on most of the output connectors. On a printed circuit board type of Splitter, typically the ONLY port that does send back the fan's speed signal is marked for the CPU, but that does NOT mean that you must plug your CPU cooler in there. This had NO effect on the header's ability to control the fans' speeds.

A HUB is a different device that has one additional "arm" that must be plugged into a SATA or 4-pin Molex power output connector from your PSU. The Hub gets all power for its fans from the PSU, thus avoiding the current limit of the header. BUT this means that the HUB can work ONLY if it is used with a header that is using the newer PWM Mode of control, and ONLY when all its fans are of the new 4-pin (PWM) type. You have at least one (maybe all four) fans of the 3-pin type, so you can NOT control their speeds using a HUB.

For this to work, the mobo header(s) used to connect the fans must be using the older Voltage Control Mode (aka DC Mode). Check your mobo manual for this detail. Most mobos these days have an option for each fan header to allow you to choose to use either the old Voltage (DC Mode) method of control, or the new PWM Mode. Some offer an "automatic" Mode chooser option but I recommend you set it to DC Mode since you know your fan type. By the way, do not confuse this option with the choice of whether the header uses the "normal" or "standard" or "automatic" type of control, versus things like full speed, or slower and quieter, or custom setting.

 

[Wolfshadw]

I mean, I do not have the manual because I haven't bought the PC yet?

Manuals are available online from the motherboard's support page. If you know what motherboard you are going to get, go to the support page for that board and download the manual. It will tell you how many fans you can connect.

-Wolf sends

 

[zuhc]

It would have helped if you had told us exactly which "this motherboard" is.

The Deepcool unit is a 3-pin design. Most fans included with cases also are 3-pin, so you should plan your connections assuming all 3-pin fans. That means two details to adhere to (see below). But for starters, check the mobo manual for a spec of the max current each fan header can supply. Most are 1.0 A max; a few are more, and I've seen some only 0.5 A. The four fans you specify total 0.66 A total, so for most mobo headers you CAN connect all four fans to a single header if you wish. Or, if you have more headers available, split them up into smaller groups.

For 3-pin fans you MUST use a SPLITTER to make groups - you cannot use a HUB. What's the difference? Do NOT rely on the name the seller gives! A SPLITTER is a simple device that has only two types or "arms" (if a group of cable arms) or connectors (if a small circuit board). There is ONE "arm" ending in a 4-pin female fan connector that must plug into a mobo fan header, either SYS_FAN or CHA_FAN. There are two ore more male (with pins) output "arms" or headers where you plug in your fans. The Splitter merely connects all of the fans in parallel to the Ground and +DCV lines from the header, so all of the power for the fans must come from the header and it is limited to that header's max current spec. Now, a mobo header can deal with the speed signal sent back to it from only ONE fan. So a Splitter will send back only one fan's speed signal and ignore the others. Often this is done by simply omitting Pin #3 on most of the output connectors. On a printed circuit board type of Splitter, typically the ONLY port that does send back the fan's speed signal is marked for the CPU, but that does NOT mean that you must plug your CPU cooler in there. This had NO effect on the header's ability to control the fans' speeds.

A HUB is a different device that has one additional "arm" that must be plugged into a SATA or 4-pin Molex power output connector from your PSU. The Hub gets all power for its fans from the PSU, thus avoiding the current limit of the header. BUT this means that the HUB can work ONLY if it is used with a header that is using the newer PWM Mode of control, and ONLY when all its fans are of the new 4-pin (PWM) type. You have at least one (maybe all four) fans of the 3-pin type, so you can NOT control their speeds using a HUB.

For this to work, the mobo header(s) used to connect the fans must be using the older Voltage Control Mode (aka DC Mode). Check your mobo manual for this detail. Most mobos these days have an option for each fan header to allow you to choose to use either the old Voltage (DC Mode) method of control, or the new PWM Mode. Some offer an "automatic" Mode chooser option but I recommend you set it to DC Mode since you know your fan type. By the way, do not confuse this option with the choice of whether the header uses the "normal" or "standard" or "automatic" type of control, versus things like full speed, or slower and quieter, or custom setting.

Oh yeah.... It's a B450M-HDV R4.0, I mentioned it in my earlier posts. Sorry

 

[Paperdoc]

That mobo has some significant limits on how it deals with fans, so let's look closely. It has two CHA_FAN headers: CHA_FAN1 has four pins, and CHA_FAN2 has three. But the info on p. 28 of the manual for that CHA_FAN2 header with 3 pins indicates that it can NOT control any fan speed. It says that Pin #2 only has a fixed +12 VDC supply which would run any fan full speed all the time. So the 4-pin CHA_FAN1 header is the only case fan header capable of controlling fan speed.

Then we run into another possible problem. On that same manual page it indicates that the CHA_FAN1 header is using the new PWM Mode of control signals. Then on p. 68 the options for configuring this header do NOT show any other option for it. IF that is true, then this mobo can NOT control the speed of ANY 3-pin fan. Such fans on this header would always run full speed. Now, it is possible the manual is wrong on this detail. You see, if a 4-pin fan is plugged into a header using the older Voltage Control Mode (aka DC Mode) its speed still CAN be controlled by such a header. AND such a header CAN control 3-pin fan speeds, too. So a header operating this way (does NOT matter how many pins it has) can control either fan type - it's sort of a "universal" fan header. The manual does NOT say this applied to CHA_FAN1, but maybe it does. The only way to find out is to connect some 3-pin fans to it and see whether their speeds change.

 

[zuhc]

That mobo has some significant limits on how it deals with fans, so let's look closely. It has two CHA_FAN headers: CHA_FAN1 has four pins, and CHA_FAN2 has three. But the info on p. 28 of the manual for that CHA_FAN2 header with 3 pins indicates that it can NOT control any fan speed. It says that Pin #2 only has a fixed +12 VDC supply which would run any fan full speed all the time. So the 4-pin CHA_FAN1 header is the only case fan header capable of controlling fan speed.

Then we run into another possible problem. On that same manual page it indicates that the CHA_FAN1 header is using the new PWM Mode of control signals. Then on p. 68 the options for configuring this header do NOT show any other option for it. IF that is true, then this mobo can NOT control the speed of ANY 3-pin fan. Such fans on this header would always run full speed. Now, it is possible the manual is wrong on this detail. You see, if a 4-pin fan is plugged into a header using the older Voltage Control Mode (aka DC Mode) its speed still CAN be controlled by such a header. AND such a header CAN control 3-pin fan speeds, too. So a header operating this way (does NOT matter how many pins it has) can control either fan type - it's sort of a "universal" fan header. The manual does NOT say this applied to CHA_FAN1, but maybe it does. The only way to find out is to connect some 3-pin fans to it and see whether their speeds change.

Ok, so moving back to the point.. I can apply all 4 of my fans into one header right? 4 of my fans are 3 pins, and maybe Id like to connect them to the 4 pin header, since I can control them, right?

 

[Paperdoc]

Yes, you can connect all four of those fans to the CHA_FAN1 header and it will not overload the header. As I said, whether or not it can actually automatically adjust fan speed is not totally clear in the mobo manual. The manual indicates it cannot, and then all the fans will run full speed all the time.

How can you tell? By trying, AND observing carefully. Connect all four fans to that header. Open the case and watch them carefully right as soon as you start up the system. The normal sequence when you start up a cold system is that ALL fans will start at full speed right away. Then, in about 5 to 10 seconds they all will slow down to what is needed to keep the system cool enough, and after that they may speed up and slow down as your workload changes. So, IF you see the initial full speed followed by all fans slowing down, then the header IS able to control all their speeds. Try this and see what happens.

IF the fans all stay at full speed all the time, the header cannot control the speed of 3-pin fans. In that case you have three choices. You can ignore this issue and accept it. You can replace all the fans with 4-pin fans. Or you can buy and install a particular fan HUB by Phanteks. It is unique mong Hubs becasue it uses a 4pin mobo fan header in PWM Mode for its control signals, but it then CONVERTS that system into the older Voltage Control Mode to control 3-pin fans properly. IF you need this, post back here for details on how to install and use.