Chassis Fan Revisions - Advice Needed!

I built my first major gaming/editing rig at the start of last year. 12 months on (and with the water cooling loop due a clean) I wanted to take the opportunity to reassess my setup slightly.

Largely the system has been running like a dream (apart from some issues with screen tearing in most games). It's running stable with a decent OC on the CPU (temps rarely exceeding 50C when mid-game).

My main gripe is with the system's fans...

I bought a bunch of NZXT FX-140LBs. Have 2 strapped to the front as intakes and 2 strapped either side of my XSPC EX280 rad in push/pull exhausting air from the top of the system (this rad only cools my CPU for now as the GPU has its own cooling built in). These 6 fans are all plugged directly into my ASUS RIVF.

I have another 4 emergency fans that are plugged in to an NZXT Sentry 2 fan controller just incase things got a little too heated. The first 2 are placed inside the case to direct air flow up towards the GPU, the third sits at the top of the case towards the front as an exhaust, and the fourth sits at the rear as another exhaust. I've not had to turn these on once and feel they are a bit overkill. I'm considering removing them entirely.

My issue with the 6 fans plugged into my Mobo is that they seem a little noisy even when on the lowest speed setting. I'm pretty limited in options to control them. One of them has also started rattling when the system is first turned on. It stops after a few minutes but as it is still under warranty I'm going to send it off to get it fixed.

Ideally I wouldn't have to replace any fans and would either...

- have 2 rad fans running when the system turns on and then the remaining 4 fans would kick in if temps went too high

or

- I'd run all 6 fans under 40% speed to quieten them down a bit.

However, I've tried using SpeedFan but it doesn't seem play all that nicely with the RIVF. I've been using AI Suite II's Fan Xpert but control through that is limited - I can't control individual fans, set them to turn off at low temps, or decrease speeds below 40%. Apparently Fan Xpert 2 solves this but it only works with AI Suite III which isn't available for the RIVF. I played around with Q-Fan in BIOS yesterday and set profiles to silent but it pretty much achieves the same result as Fan Xpert.

I could use a manual controller but to be honest I'm pretty underwhelmed with the Sentry 2. I would prefer a solution that automatically adjusted speeds and turned fans on and off for me so I don't have to keep watching temps.

I've been looking at the Phanteks PH-F140TS as a quieter alternative to the NZXTs if there simply is no other way. However, as they cost about £16 a pop I want to make sure that I definitely don't have another option for having more control over the fans I already have.

I'm going to play around with the number of fans that run at any one time to see how that impacts temps and noise but thought I'd seek out some further wisdom here...

Thanks!

P.S. The NZXT fans I already have are not PWM fans. How much of a difference would PWM make?

OK to start with, speed setting have you got them on?
the FX 140LB uses the same speed control switch as the old Antec tricool fans, a small cable with a selector switch attached with 3 speed settings, low/medium/high (1000rpm/1500rpm/2000rpm)
The issue you will have here is that this type of fan doesn't like being controlled outside of the built in switch.

A quick basic lesson in fan control, a fan should run around it given rpm (nominally +/-10%) at 12v, a fan controller works by simply adding resistance between the 12v power source and the fan, there by reducing the voltage and slowing the fan down.
The same goes for motherboard software control, speedfan, fan xpert or what ever software you use, does the same basic thing, it uses the motherboard power regulation to reduce the voltage to the fan headers.
Normally the cpu fan is on a separate regulation source so can be adjusted at a different rate from the rest of the headers.
Now depending on your motherboard you may have a chipset fan header which is also on separate regulation, your "system" fans may or may not have any regulation and you may have a "pwr" fan header which is never regulated (this is an old one back from when some psu's had a fan lead and the fan header is simply designed to monitor your psu fan in case it fails and on some older motherboards the pwr header didn't even supply power)

The problem with control via voltage is that most fans stop working below 5v (or 40% speed) as the motor no longer develops the torque required to turn the blades, this can damage the motor, so most fan controllers will not go lower than 5v

a quick note about fan controllers, often the control they give is given in a %, while 0% might well be off, the next lowest step is normally 5v, so 1% is not 1% fan speed it's often 40% fan speed (5v)

PWM fans work in a different way, they have a 4th wire which is a control signal, they work at a constant 12v but are pulsed, basically turned on and off very quickly, the faster the pulse rate the slower the fan spins.
This allows for a far greater range of speed and an automatic cut off, when the pulse rate goes over the maximum the fan allows it just treats it as a stop signal and the power is cut to the motor.

This is where your fans now come in, the speed select switch is basically adding in resistance to the power feed of the fan so on high it runs at 12v, medium around 9v and low around 6v
So if you change the switch from high and use a fan controller you are reducing the input voltage and adding in additional resistance to drop the final voltage even more, this might get your fans slower and thus quieter but could well go below the minimum voltage the fan needs so it stops and could damage the motor.

The next thing is your setup, 4 fans on a water block and 2 on the case front.
fan xpert is a great system allows for some fine control (set it to custom and adjust the temperature/speed graph to a point you are happy with.) however due to the system it uses you have a major potential problem.
motherboards tend to take two temperature readings, system and cpu, the cpu fan header is the only one controlled by the cpu fan setting, all the other controlled fan headers use the system temperature numbers for their control, so if all 6 fans are connected to different headers then only one is probably reacting to the cpu temperature the rest are reacting to the system temperature (which is roughly the ambient temperature inside the case)
So if all you are doing is changing the cpu fan control you're only actually effecting one fan plugged into the motherboard cpu fan header.

For the setup you have if you wanted to go to PWM fans, you'd want 4 of them for the radiator, then connect them to the cpu fan header via a 4 way splitter cable eg http://www.scan.co.uk/products/ek-ca...n-pwm-extended
Then you set the fan speed control via the BIOS or software for the cpu

However I'd look at your current setup first, could well just make changes to that which will give you good results.

There's a long standing argument in water cooling circles as to if it's better to set the pump to a fixed speed and control the fan speed or to fix the fan speed and control the pump speed.

Another point to note is that push pull does help lower temperatures it's not an amazingly great effect, the amount of effect varies greatly depending on the air flow restriction of the rad and the pressure the fans generate, but it is something to test as to if it's worth it on your setup and you will have to test it yourself to see.

One of the thing about cooling is that there's no easy answers, especially why you throw something like noise which is very personal (what you say is loud I might say is fine), so you will need to spend some time testing your own system to get optimal results.

Thanks for the info!

I have all fans on their lowest setting via their built in speed control switches.

As far as I can remember I have all 6 fans plugged into chassis ports on the Mobo (I'll double check tonight). Makes sense that Fan Xpert etc uses chassis temps to control chassis fans. Hadn't even crossed my mind - bit of an oversight!

My mobo has 2 CPU fan connectors, 3 chassis, and 3 optional.

Perfect thanks again. I'll try and have a play this weekend and see the minimum number of fans I can have running but still keep temps in ideal range.

If I scrap the push/pull set up how would you suggest I arrange the fans on the rad? Been reading a few conflicting pieces of advice...

1. Put them under the rad pushing air up through it and out of the system
2. Put them on top of the rad pulling air through it and out of the system
3. Put them on top pushing air down through it and into the system

With my current set up I followed advice that suggested I should have more air exiting the case than coming in.