Question Do I need a PWM splitter or HUB for my fans?

[RandomGuy1299999]

Im building a PC, the parts brought already are listed as $0.00. I was wondering, to connect all my 6 fans to my PC for all of them to work, would I need a HUB or splitter? I want to make sure my fans will be able to have color, and also have all similar speed control/power. I'm not sure If I needed something like this for it to happen.

I also have some RGB splitters, "Jstincal ARGB Splitter Cable, 1-to-4 Female to Female 5V 3 Pin Addressable RGB Splitter Extension Cable ARGB LED Sync Cable for Computer Chassis CPU Cooler and 5V ARGB Fan (2 Pack)". I'm not too sure if they are compatible for my motherboard, I'm not too familiar with PC parts and how to know if things are compatible or not.
Will these RGB splitters be enough? or again will I also still have to have a HUB or another splitter for all my fans to work.

I heard some guy said I can connect 2 pairs of 3 fans together (daisy chained), and then connect them to the motherboard and it should be fine so I wont need a PWM splitter or HUB. Is this true?


My list: https://pcpartpicker.com/user/RandomGuy_19013/saved/nJnVD3

 

[Lutfij]

Welcome to the forums, newcomer!

The 3 fan packs come with a 3-to-1 splitter. Each splitter can go onto a PWM header on your motherboard. If I was in your place, I'd just pick up a PWM hub for al the fans as well as an ARGB hub for the lighting, that way I only use one header on the motherboard and the hubs have all the fans and ARGB hooked to said hub.

If you want to move with splitters, the max number of ARGB devices off of one header is 5.

Oddly enough ASRock's website isn't working for me, which is why I can't certainly say how many headers you have access to..

 

[RandomGuy1299999]

@Lutfij
Hi! Thanks for the reply, do you have any recommendations for any of the hubs? Also do they sell the hubs individually meaning I will have to get an ARGB hub and a PWM hub separate? I have seen some hubs that I'm pretty sure have ARGB and PWM together in one hub but not 100% any recommendations? Would I also have to buy some extra cables or nah?

Also after looking online it seems that there are 4 headers total?
https://download.asrock.com/Manual/Z790 Lightning WiFi.pdf

 

[Paperdoc]

You do NOT need any Hub or Splitter for your system. Before details, some general info to help understand.

Fan motors come in two types: an older design with THREE pins with which speed control is done only by varying the Voltage supplied to the fan, and a newer design with FOUR pins called PWM type in which power is supplied at a fixed 12 VDC and ALSO a PWM signal is supplied for speed control. All your fans are this latter type.

Your CPU cooler system contains a fan with no extras. All your case ventilation fans are LIGHTED - in particular, they contain Addressable RBG (aka ARGB) lights in the fan hub. In essence these fans really are TWO devices in one unit - a fan motor, and the lights - each with their own separate cable to go to different mobo headers. In your particular fans, for each of these cables they have made them with both male and female connectors on the ends. This allows you to connect several fans' motors together in a "daisy chain" to ONE mobo fan motor header so that you do not need to buy an extra Splitter. The mobo header is male (with pins), so the female motor connector from one fan goes to that. Then the next fan's female motor cable goes to the male from the first fan, and so on. There IS a limit to this. The mobo fan header can supply power to all fans on that one header up to 2.0 A max current for most of your headers. (Exception: CHA_FAN5 is limited to 1.0 A.) Now, each fan is rated to use up to 0.20 A current. So hypothetically you could make a "daisy chain" of up to 5 such fans all connected to one mobo header. I would recommend you do not do that. Instead, arrange the six case fans into two chains (3 fan each) or into three chains (two fans each) and use two or three mobo headers.

FYI, any one fan header can deal with the speed signal sent back to it from only ONE fan. So when you connect more than one fan to a header (via daisy chain in your case), that header can "see" and report the speed of only the first fan in that chain, and the others in the chain are never "seen" anywhere. This does NOT affect ability to control all the fans in the chain - you just assume they all are doing the same thing since they all are the same fans. However, each fan motor header ALSO does a second function: it monitors the fan's speed signal for NO speed which indicates failure, and will pop up a warning on your screen if that happens. But in any daisy chain it cannot "see" the speed signals of those "other" fans and cannot detect failure in those. So from time to time YOU just need to look in and verify that all your case vent fans still are working.

In a similar manner, the fans' LIGHTING cables have the same structure, so you can daisy-chain those, too, and connect to any of the mobo's three ADDR_LEDn headers. These headers also have their own current limit of 3.0A each. I did not find any spec of LIGHTING current for those fans, but I am SURE each is less than 1.0 A, so two or three fans' lights in one daisy chain to one header is OK.

So that gets all the fans' lights and their motors connected to power and control. You want them all to do exactly the same things, and that is accomplished merely by configuring each header you use exactly the same. See the Software / BIOS Setup guide for that mobo on p. 79-85. On p.79 note you can select each fan motor header at upper left, then configure that header only. After doing this for all headers you use, click on Apply at bottom right to save all settings.

For each fan motor header in use, set this way:
For Control MODE (this is NOT shown in the manual screen shot) set to PWM for your fans, NOT to Auto or to DC.
For all headers with this option, ensure it is set to FAN and not to PUMP.
For Fan Setting, set to Standard to use the pre-set "fan curve" for speed control. Custom settings can be done later AFTER you have it all working and know whether or not some adjustment is needed.
For Temperature Source for all case vent fans set to Monitor M/B, not to Monitor CPU.

When you have set all your motor headers this way, click on Apply, then use the Esc key to get back to the Main Menu - see p. 26. There at upper centre click on PolyChrome RGB until it says ON to turn on the lighting control software system. The just to the left of that click on the little floppy disk symbol to get to the Exit Menu (p. 93). There click on Save Changes and Exit to do that and reboot your system.

The installation process for your mobo that installs all its device drivers from its CD of utilities also should have installed the Polychrome RGB software tool. Use that to configure all the LIGHTING headers you are using. I do not have any manual for that tool. It may just set all the headers the same, OR it may allow you to configure each individually. If you want them all to do he same thing, set them all identically and ensure they are Synchronized.

 

[dwd999]

Yeah, I think I'm the guy who wrote what he's referring to. And yeah, I do have 7 Lian Li SL-INF fans in banks of 3, 3, and 1 connected to 1 argb motherboard connector with a Jstincal ARGB 3 way splitter cable and they work just fine, even at 100 percent white. But I do have the fans PWM cables connected to 3 PWM headers on the motherboard so the 3, 3 and 1 banks of fans are PWM controlled separately.

 

[RandomGuy1299999]

@Paperdoc
Wow thanks for the in depth reply! Im a newbie to PC building so your message helps, thanks!