Fan Controller vs Using Motherboard

[Mehta23]

Hi,
I'm wondering what the best plan of action is to be able to control the 6 fans (Inc cpu) in a Zalman z11 (not mine).
In my case I've just plugged the 3 fans into the motherboard and can control the speeds with software relating to the temperature of my cpu...
I'm new to the idea of fan controller so it would be appreciated if someone could give me an overview of why you'd get one and if it would be better than using a PWM splitter on the motherboard...

TIA

[mikeo01]

May be a bit biased here seen as I have only used low end cheapy fan controllers, but I find fan controllers to be a bit annoying, especially the non-automatic ones.

It's essentially a PCB with different voltage lines connecting up to standard 3/4-pin headers. Then it's a simple case of wiring it up to a molex, usually. I am not sure on some of these high end controllers.

Software seems fine for me, I personally use a splitter, sure may be more cables all over the place. As long as you don't draw the power from the motherboard it's pretty much the same concept.

I personally would prefer PWM splitter with molex adapter because it's just easier and much cheaper. I use all my fans on the single CPU header so they all ramp up with CPU heat.

But that's me

[Mehta23]

The splitter you talked about in your second is probably what I'll get then - the one found uses a molex from the psu and then powers several fans.

[mikeo01]

This splitter seems decent Here

I use the Akasa Smart PWM Splitter, does the job, isn't sleeved though.

[Pob255]

Software fan control is often very dependent on the motherboard
All motherboard will allow control over the 4pin pwm cpu fan but other headers are dependent on the motherboard.
You can get simple 2fan splitters for 3pin fans http://www.scan.co.uk/products/30cm-...e-2-molex-male you generally don't get more than two to stop you overloading the header (most of the ones with more than 2 fans have a molex or sata power connector for additional power, but as they get power from the psu you cannot change the rpm unless they are PWM fans)

Fan controllers vary greatly, the cheap ones are simply cheap rheostats (variable resistors) you turn the knob to change the resistance reducing the voltage and thus the speed of the fan, the advantage are they are cheap and give you quick manual control over the fans

More expensive ones add in control chips and thermal sensors, these allow control via manual or automatic temperature control.

A pwm splitter will only work on pwm fans not on normal 3pin fans

Simple cheap options
fan controller http://www.scan.co.uk/products/asete...otherboard-kit add it a splitter cable to run multiple fans off it, although I'm having trouble finding the specs for that, so I'm not sure how many fans you could run off it.
or a bunch of voltage resistors http://www.scan.co.uk/products/shark...m-and-noise%29 or http://www.amazon.co.uk/Zalman-ZM-RC.../dp/B0015DA0YM you can use these on motherboard or off a molex to 3pin adaptor, down side is it's not adjustable
the Akasa 3.5"bay fan controllers http://www.amazon.co.uk/gp/product/B00B4T2COS or http://www.amazon.co.uk/gp/product/B00B4T2CP2 these let you control 3 fans and give you additional front usb ports off spare internal motherboard headers

bit more cost Control 6 fans from a 5.25" bay http://www.specialtech.co.uk/spshop/...pid-14380.html

[Mehta23]

So you have to have a PWM fan to control the speed?
I know in my rig (storm enforcer/Asus p8z77 vlx) I can control 3 fans from the motherboard. I have no idea what can be controlled in my friends build - Zalman z11/gigabyte ds3h

[Pob255]

No you don't but you do if you want to use a PWM splitter cable.

PWM fans work via that 4th wire which sends a pulsed signal to the fan telling it to turn the motor off, it's constantly powered by 12v but by pulsing the motor on and off it slows the fan down.
The PWM spliter cables split the 12v and PWM signal across all the fans so they all receive power and PWM signal
If you plug a 3pin fan into it the fan will run but at the full 12v speed and not be controllable as it's not getting a pwm signal.

3pin fans run at a fixed 12v but you can reduce the voltage making the motor run slower, how well the fan will run is dependent on the fan, most fans will still work at 5v but not all fans, some fans will run if they where spinning but if they where not moving then 5v might not be enough to start them.
For this reason many motherboards don't allow you to drop the voltage on a header below 6v, or will run the voltage at the full 12v at first to get the fans sinning before dropping the voltage.

On the Asus p8z77-v lx it has 3 4pin pwm headers which can also be software controlled in 3pin mode by reducing the volotage, it also has a 3pin header which is actually designed for a power supply (some psu's have a fan connector to allow the motherboard to monitor the psu fan) you'll probably find that that fan header cannot be controlled.

I take it your friend has the GA-Z77-DS3H (although there other models that end in DS3H) that has 4 pwm headers that should also be controllable via 3pin voltage reduction mode.

Some of the more expensive fan controllers actually work via a PWM function even with a 3pin fan, but work by pulsing the 12v power instead of reducing the voltage or sending a separate signal, but not all 3pin fans respond well to pulsed power which is why motherboards normally control 3pin fans via voltage reduction.

[Mehta23]

Thanks so much! I understand now! :-P so my friend should be fine to just plug the fans into the motherboard as long as he doesn't use a PWM splitter?
I can't remember his fan setup exactly but I think the main problem was having 3 fans that needed molexs

[Pob255]

From what I remember of the Z11 plus the problem is likely to be the two 80mm fans in the side panels.
One thing you can do with molex fans is to get or make a crossover cable, basically a short extension cable that swaps the pins over, by swapping the 12v and 5v pins over you can make the fans run at 5v (you'd need to double check the fans will work, but 80mm fans don't normally have issues with 5v, tends to be 120mm and 140mm fans that are more likely to have issues) or you swap one of the earth wires with the 5v to setup resistance so the fan will run at 7v
This is safe to do in regards to a fan, however it does create additional "noise" on the 12v which can potentially cause issues, mainly for overclocking.
And of course do NOT plug anything except fans in after a molex crossover cable, before the crossover is fine, just not after it.

If the fans are running off a molex to 3pin adaptor then you can just add in simple resistance adaptors (like I liked before) to slow them down a bit

[fatguy666]

I've got the CM 690 II case which has similar drive covers to the Z11. I run my CPU fan from the motherboard but for my case fans I got this controller http://www.scan.co.uk/products/nzxt-...ller-525-black which matches in nicely plus has an old school graphic equalizer look

Rarely feel the need to turn them up unless I'm playing something hardcore.