Fan control questions

Control: management of fans, temp/rpm monitoring via soft/hardware

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DeltaForce
Posts: 75
Joined: Sat Jan 20, 2007 10:30 am
Location: California

Fan control questions

Post by DeltaForce » Wed Apr 11, 2012 3:40 pm

Hi,

I'm ready to build a new machine after being delayed for months, and want a good fan control solution. My use is very quiet for work and Internet, and high airflow for gaming for hours. Generally I prefer to be Lord of the Fans and have manual control on all except the PSU and GPU. Or do motherboard utilities like ASUS fan xpert work well?

1) What's a good controller solution? Do I use an advanced controller with sensors, or use software and sensors with a simple knob controller? Does a sensor have to be put manually in the GPU? In my current computer I don't know temps aside from looking at the bios at idle. Some brands are nzxt, scythe, and zalman. Is there software I need? This would go in a fractal R3 or Corsair 550D, and both might have clearance issues with the front panel door. Cost is not an issue (I'm saving in other ways).

2) Is it possible to turn fans on/off without opening the case? Can this be done in the bios nowadays, or is there an on/off switch that could be connected on the back of the case to the fan cables? For example on the 550D I could keep the top cover on for normal use, then open it and turn on additional fans when gaming. I don't mind that extra effort in normal use at all.

3) How much does the single bottom fan on an R3 or 550D help with temps under high load? The PSU I wanted is long and may cover the bottom fan placement slot.

Thank you!

ces
Posts: 3395
Joined: Thu Feb 04, 2010 6:06 pm
Location: US

Re: Fan control questions

Post by ces » Wed Apr 11, 2012 9:41 pm

Performance-PCs.com has, I believe, the most extensive stock of fan control devices around. See:
http://www.performance-pcs.com/catalog/ ... Path=36_48

paapaa
Posts: 198
Joined: Wed May 04, 2005 1:24 am
Location: Finland

Re: Fan control questions

Post by paapaa » Thu Apr 12, 2012 12:25 am

I'd build a system that is capable of maintaining decent temperatures always with no need to alter fan speed at all.

1. Get a good semi-passive PSU. Kingwin/Super Flower has PSUs which remain passive under 400W. And don't overestimate your power needs. Most likely your high-end gaming machine always uses less than 400W of power.
2. Get big heatsinks for CPU/GPU with big slow fans.
3. I'd use BIOS/hardware to control the speed if needed. New mobos have quite good ways to control the fan speed.
4. You don't need to aim for the lowest possible temperature. GPUs can handle high temps easily. Just make sure they stay in the safe zone. So no need to turn your case into a hairdryer while gaming. Being the Lord of the Fans is probably not needed at all.


What hardware you are planning to buy?

lodestar
Posts: 1683
Joined: Fri Aug 05, 2005 3:29 am
Location: UK

Re: Fan control questions

Post by lodestar » Thu Apr 12, 2012 4:19 am

DeltaForce wrote:My use is very quiet for work and Internet, and high airflow for gaming for hours.

1. Some motherboards are better than others when it comes to fan control. Asus are probably the best because you would normally get both a choice of fan profiles and the ability to set a manual profile in the BIOS. For most people the Silent profile could be enough. But with the manual profile you could set the fans to the speeds you wanted at idle and at load.

If the Asus BIOS controls are not enough, then Fan Xpert offers more options if necessary. With gamers it is quite common to set up a PWM fan chain of either CPU plus exhaust, or CPU, exhaust and intake. This would give thermal control of case airflow rather than just CPU cooling. Existing case fans can be deployed to other positions, and could be plugged into the motherboard chassis fan headers. Asus motherboards typically give you a choice of fan profiles in the BIOS for the chassis fans as well, and also a manual profile, with again the additional flexibility from Fan Xpert if required.

2. A PWM fan can be turned off if its duty cycle can be set to 0% and 0%=0 rpm. Many fan manufactures set 20% or 30% as a minimum and even this may correspond to something like half the fan's nominal speed. But if you really do want 0% duty cycle=0 rpm then the recently introduced Noctua PWM fans will do this. I am not sure if turning a fan off is really necessary, the Noctuas for example would be extremely quiet at their normal minimum of around 300 rpm. But Asus motherboards do allow a minimum PWM duty cycle setting of 0% for the CPU in the BIOS manual profile, so you could set up a semi-passive profile where the fans were off until a set temperature was reached.

3. Bottom fans help because they supply air directly into the GPU intake area. Having said that, on the 550D the intake fans can be mounted on the drive cages and would then supply air directly in the same way, but would be pulling it over any hard drives which might make a difference to intake air temps.

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