Whats the best method to split up multiple RGB fans on one header?

[bennyy279]

Hello,

I've done some searching around and got mixed results some say use a splitter then have the fans connected to that and splitter connected to the mobo and people say use a hub to split fans up. So I don't know which is the best way to go about it, as I know my mobo only supports one RGB header, not sure of its max amperage is but I think most are between 2-3A? Also I know this off-topic and I apologize but could someone also recommend a decent aftermarket cooler for my CPU?
Preferably that isn't bulky as hell and tricky to fit with big hands, been there done that...

Lastly, in terms of splitting of RGB fans I would like to if possible power 3 or more if an aftermarket CPU cooler doesn't take up the space at the top, but not essential mainly 3, exhaust and two at front of case.

Thanks in advance!

 

[Paperdoc]

The answer depends on two things we need to know. But before that, a bit of explanation.

Cooling fans come in two types now, for the most part. The older design are 3-pin fans. The motors have 3 wires ending in a connector with 3 holes. The wires are Black, Red and Yellow. The connector has some ridges on one side, and the male (with pins) header on a mobo has a plastic "tongue" sticking up beside its first 3 pins. When you plug in, the ridges fit around the tongue so there's only one way to get them together. The ONLY method of controlling the speed of a 3-pin fan is called "Voltage Control Mode", in which the + VDC power supplied on Pin #2 (Red wire) is varied from 12 (max) down to 5 (min).

The newer fan type is called 4-pin and surprise! it has 4 wires (different color codes) and a connector with 4 holes. The connector design is VERY like that of a 3-pin fan with ridges on one side so that it can plug into the mobo header. A mobo header for this system has 4 pins. Big surprise there, too! In this fan type, Pin #2 has a constant +12 VDC supplied, and the new Pin #4 carries the PWM signal. Inside the fan there is a small chip that uses the PWM signal to modify the flow of current from the +12 VDC supply through the motor windings to achieve speed control. The new design includes backwards compatibility features so the you can plug any 3- or 4-pin fan into any 3- or 4-pin header and they will work. Well, with one important limit: a 3-pin fan plugged into a 4-pin header that uses the new PWM Mode of control will always run at full speed, so you get good cooling but no speed control. The other mis-match (a 4-pin fan connected to a header using Voltage Control Mode) works just fine with speed control and all, but this is not quite as good technically as using PWM Mode to control the 4-pin fan. All fans generate a speed signal (a series of pulses, 2 per revolution, sent back to the mobo on Pin #3 for counting. However, this signal is NOT used for speed control, but it is often used to monitor the motor for failure. The number of pins on the mobo fan header does NOT tell you what method (Voltage Control Mode (aka DC Mode) or PWM Mode) it uses for contrl of fan speed. In fact, most mobos now use 4 pins on all headers, but various methods of fan speed control.

There are two kinds of devices for connecting several fans to a single mobo header. A SPLITTER has one arm with a female fan connector that plugs into a mobo header. Then it has two or more output connectors for fans. All of the fans are merely connected in parallel to the power supply lines from the mobo. Most mobo headers can supply up to 1.0 A total current to all fans connected to that single header, so there's a real limit on how many fans you can handle with a Splitter - often 3 or 4 max with a "normal" fan. Any mobo header can accept only ONE fan's sped signal for counting, so a Splitter (or a Hub) will send back to its header only ONE fan's signal, and ignore all the rest.

A HUB is similar electrically and can have several physical forms. What makes it different, though, is that it has an additional third arm type that must plug into a power output connector from the PSU (either 4-pin Molex or SATA output). THIS is the source of the +12 VDC power for ALL the fans on the hub, and most good hubs will NOT make any connection to the mobo header's Pin #2. Thus the 1.0 A limit on total fan load is avoided. BUT in almost all cases the HUB simply shares the fixed +12 VDC supply and the PWM signal from the header to all its fans. This system depends on using only 4-pin fans with the Hub, because all of the fans MUST be able to use the PWM signal to achieve speed control. (There are one or two Hubs that are different from this.)

When we get to "LED fans" there are some variations. Early designs had one or maybe a few colors of LED, and simply connected them to the +12 VDC supplied to the fan from Pin #2. To some extent the LED brightness changed when the fan was supplied via Voltage Control Mode with reduced voltage on the Pin #2 supply, but they work. HOWEVER, this means that both the fan motor and the LED's are drawing current from the supply, so this has an impact on the load the fan draws from the mobo header, and that is important when considering use of a Splitter. The newest LED fans come with two separate electrical cables. One is strictly for the fan, whether of 3-pin or 4-pin type. The other has a different connector and is strictly for the LED system. What is becoming common is that you get either a LED controller box or you get a mobo with an LED control header, and you connect the LED leads from your fans to those sources. If you have several LED strips or fans with LED cables, you can get a LED Hub which allows control of many LED units from one LED header. They provide both the power for the LED's and control of their lighting effects. With this fan type, the electrical loads of the LED's are NOT involved in figuring out how to control the FAN part.

So, OP, to advise we need to know:
1. What mobo - maker and exact model number - do you have, so we can look up its manual and see what its fan headers can do? Also, whether it has an LED header.
2. What case ventilation fans do you have (or plan to get) - again, maker and exact model numbers for each fan. We can look up how each is controlled and its wiring and current consumption details.

 

[bennyy279]

Hey,

Thanks for that very detailed explanation! It's been quite some time since I've messed with computers and rightly so I'm use to the old design so I'm still relatively new to these ones. The motherboard I have is the Gigabyte X470 Ultra Gaming. In terms of what fans I've not set myself on anything as of now was hoping to get recommendations from others rather than me spending money and end up with wrong ones and so on. I did check the manual on this mobo it had one header near the CPU which I've used to connect to the stock AMD cooler that came with my Ryzen 7 2700X. All I have now on this case is just two fans at the front of the case and as far as I know they are just standard fans no RGB connector to them, but my aim is just transform the case with RGB fans (as in exhaust, possibly upper exhaust if its possibly with an aftermarket cooler when I get one and then later on swap out the two fronts for RGB ones instead) of course if that's possibly within the limits of this board.

Again, thanks.

 

[Paperdoc]

OK, you have ample resources in that mobo to do what you plan. If you don't have its manual now, get it here.

https://www.gigabyte.com/Motherboard/X470-AORUS-ULTRA-GAMING-rev-10#support-dl-driver-audio

Click on the "Manual" heading to get the menu.

See manual p. 14-15 for fan header details, and p. 27-28 for general info on configuring fan headers individually in BIOS Setup. First, CPU cooling. You already have the stock CPU cooling fan in place using the CPU_FAN header. When you replace that with a liquid cooling system, you will use that same header for at least part of the new system, and may need also the CPU_OPT header (see p. 14-15). Details depends on the instructions with the new cooler system.

For case cooling you will be using the SYS_FAN1 through 4 headers. (SYS_FAN5 and 6 are intended mainly for use with more complex liquid cooler systems). Each of those fan headers can supply up to 1.0 A to fan(s) connected to them, so you can use that in planning your connections. If you need to connect fans requiring more than 1.0 A total to a single header, you will need a Hub to do that, but be aware that most Hubs will ONLY work with 4-pin fans, NOT with 3-pin ones. Each of those SYS_FAN headers can be configured to use either Voltage Control Mode (aka DC Mode) or PWM Mode to control its fans. If you have 3-pin fans, you MUST use Voltage Control Mode; for 4-pin fans, PWM Mode is preferred. You also have LOTS of choice in temperature sensors. Every fan header uses (by default) automatic control of its fan's speed. Really, it is TEMPERATURE control in each case - that is, the control system's focus is on the actual TEMPERATURE as measured at a sensor, and it manipulates fan speed to achieve its temperature target at all times. There is always a sensor built into the CPU chip itself and fed out on a pin to the mobo for use by the CPU_FAN header. Other headers may also be set to use that sensor. This mobo has seven additional sensor built into it, and each may be chosen as the one to guide any of the SYS_FANn headers. There will be one as a "general" mobo temp sensor, and others that are specifically for particular key components like the voltage regulator, the North Bridge, etc. These specific ones are available in case you wish to position a fan just right to cool a particular mobo component, and then set that header to use that component's nearby sensor. In many situations that will not apply and the "general" sensor is suitable. Usually you do NOT use the sensor inside the CPU chip for guiding case vent fans.

As a general rule these days, I'd recommend buying 4-pin fans which have slight technical advantages over the older 3-pin design. You may well find, though, that any fan supplied with a case is 3-pin, and you may find you prefer a 3-pin design for some things, and that is just fine - your mobo can handle that. If you are buying LED fans

See manual p. 15-16 for details of THREE headers used to power and control LED strips or the LED components of lighted fans. For your purposes, you should choose fans that have the LED parts wired separately from the fan motor. Then you can check to be sure the LED wiring matches one of the systems supported by the headers on the mob. This will allow you to use software utilities and the mobo capabilities to control those LED's, completely independent of what you do with your fans.

 

[bennyy279]

Okay, thanks for that I do have the manual still in the boxing for the mobo so I'll use that. I'll most likely go down the hub route and get fans that have the 4-pin design then go from there getting it all working correctly. Again, thanks!

 

[Paperdoc]

You're welcome, and thanks for Best Solution. Have fun with your build!