Hey all, I've recently begun the process of moving my system into a new chassis, main reason being that my current chassis does not support a Corsair H100, which in turn leads to toasty temperatures when folding. The case I'm using supports a multitude of dual 120MM fans, but due to only having half the same amount of fan headers on my motherboard, I've gone for using a fan cable splitter to allow 2 fans to be connected to 1 header. I went under the theory that each fan would only receive half the total amount of power output by the header, so therefore run much quieter, give a greater coverage (but the same CFM as a single, full powered fan) of airflow and all run without the need for a separate controller. Would this theory be correct? For reference, the fans in question are Cooler Master Sickle Flow 120MM (Red LED). Also of note, I will not be using fan splitters on my H100, but the 2 dedicated headers on the top of the motherboard for CPU fans.
My example: I have a coolermaster 830 stacker case (although old now still an amazing very large case). and is has 1x120mm front fan, 4x120mm fans on the side, 1x120mm fan in the roof vent and 1x120mm fan rear. So you can imagine not many if any motherboards support that many fans for a separate connection. I had a splitter x2 for the 4x grid of fans and i can confirm they run exactly the same speed rpm (shown on BIOS) as the others that have their own connection. Motherboard: P5Q S775 motherboard with 5x fan connections + cpu.
You need to go under a different theory. A conventional splitter will supply the same voltage to each fan. The only thing that splits is the rpm signal. In fact the rpm signal should only connect on one of the fan splitter sockets. A motherboard generally supplies at least 1 amp per header and I have 5 fans on one header. My fans actually come with the splitters built in which makes it a whole lot easier especially since they're pwm. Advantage having so many fans on one header is that the speed of all case fans can be controlled in bios or with mobo fan utility in windows. If you want quiet fans then speed control them.
I wouldn't advise doing this. I'm sure I read somewhere that you can overload the fan header on the motherboard and cause damage. That's why I bought one of these: http://www.thewatercoolingshop.co.uk/phobya-4pin-molex-to-6x-3pin-fan-splitter-pcb-81097.html
but its 2 fans only for one header is his question, and my examples been running on current mobo and tower for the last 4 years... Maybe more than 2 but the amperage is hardly to change. and all my fans are blue LED
@Stanley - Thanks for that, very helpful. Indeed, only 1 of the 2 connections on my splitter is 4 pin, the other, I think has only 2 pins. Having an Asus ROG motherboard, fan control software is built in so I will have a good play. @scuppy - Interesting, I've not heard of it but will Google it now to investigate. That little Molex to 6 3 pin headers is brilliant though, definitely a cheaper alternative that a fan controller, but you loose the ability to control the fan speed.
Scuppy may have read it somewhere but it's absolutely not true. I don't know of any mobos that supply less than 1amp per header and asus manuals even state the current usually. Current is generally between 1 and 1.3 amps. You have to check the rating of the fan but the 120s are generally 200ma or less. I run 5 fans on one header. All you have to do is look at the current rating on the fan and make sure the total for all the fans doesn't exceed 1 amp. I used to make my own fan splitters back when I was using analog fans. As mentioned I now use fans with built in splitter and the booklet that comes with the fans says up to 5 on one header. I use arctic F12 pwm and they are rated at 150ma each. My asus mobo states 1amp. Incidentally I have a friend who went totally the other way and ignored my advice not to overload his fan header. He bought the same water pump as me, rated at 1.9 amps. The manual for the pump gave no warning not to power from the mobo fan header. I used the molex splitter to power mine and just took the yellow rpm signal from pump to fan header. He powered his 1.9 amp pump from the CPU fan header and 3 months later his CPU fan header burned out. I've always used splitters on my case fans to power from a single header and so long as I don't exceed that 1amp there is never a problem.
Cheers for clearing that up even for me. It must have been one of those horror stories where some moron tried plugging something dodgy in to a fan headed and fried it. The 1x molex to 6x 3pin fan is for my 4 radiator fans. The fans make very little noise so not worried about them running at full speed. Rest of the fans I have are plugged into my fan headers.
Yeah, there is always some horror story out there My 3 x rad fans are connected to the CPU fan header. 5 x case fans on another PWM header. I had a german friend who used to get told all kinds of horror stories from pepes on forums... They told him for example that applying thermal paste was really tricky and dangerous. Going into the bios was dangerous... Raising cpu voltage above default was dangerous... Eventually he listened to me and learned to overclock. That took me by surprise actually because he was generally fearful of everything. But this was also a kid who stuck a screwdriver into his computer PSU and made it go bang. After that his mother didn't trust him around computer parts anymore.
