Fan Control 101?

[Eradan]

[H]ey, guys.

Is there a basic primer/best practices guide for fan management? I've never really given it any consideration in the past, using whatever stock fans existed in a given case. My goal with my upcoming build is a balance between cool and quiet. I have no plans for any sort of extreme overclocking.

I have noticed that some cases come with fan controllers and that there are third party fan controls available as well. Asus has this Fan X-pert software, too. There also seems to be some discussion re: the number of pins a given fan cable has.

Does any of this even matter? Should I stick to my philosophy of just plugging in the stock fans and going about my business? Or is this something else that I can tweak that will yield appreciable real-world benefit?

Thanks!
E

 

[aphasia]

for a generic PC case, as long as there is an intake of cool air at bottom-front of the case and exhausting the hot air rear-top, not really.

the only time it starts to matter is if the system hosts a lot of devices (multiple HD's or GPUs), heavily OC'ed or the ambient temperature is high.

if you really want to optimise the air flow for quiet operation, you want big fans (120mm or greater) and throttle them down for silence. 1800-2000+rpm fans are preferred b/c at 50-60%, shouldn't really hear them. ideally you want more fans (or spinning slightly faster) for intake than exhaust to create positive air pressure in the case to minimise your case turning into a vacuum or dust haven.

monitor/control software is ok but unless all the case fans are hooked up to it, the case air-flow dynamic is going to get messed up. either have all the fans spinning at a set rpm to ensure positive air pressure or have them all spin-up an equal amount once a temperature threshold is triggered.

as you've mentioned your not OC'ing, just use some semi-decent 120mm (or greater if case has mounts for them) and keep your PC case off the floor to prevent the 'hoovering' effect.

regarding 3 & 4 pin fans, 4 pin fans are usually better. 4 pin fans are PWM (Pulse-width modulation) which use switching to control the fan speed. to control a 3 pin fan, a resistor is used to drop the voltage/fan rpms. PWM are far more energy efficient where as fans attached to a controller using 3 pins generate a bit of heat (depending on how far the 12volt has been stepped down). there are only 1 or 2 4pin PWM headers on a MB anyway so 3 pin fans is what your going to be dealing with for case cooling.

i'm pretty tired and i may have pulled some of that shit out of my arse. is this what you were after? (not poop, the stuff on fans...)

 

[Samwiches]

I will just add a correction, that intake doesn't have to be at the bottom and exhaust does not have to be at the top. "Hot air rising" is not something in effect when there are fans involved, and case air isn't hot in the first place; it's barely warm and will go wherever you push it. Actually the best air movement happens when you pull it---fans blow air into a messy cloud, but pull air in a much smoother and more controlled way.

Oh, does it matter? No, not unless your OC is at the limit, where +5 degrees is enough to cause instability (increased power requirement at higher temps).

 

[grambo]

I did some research on this as I wanted similar outcomes for this build. I wanted it to be quiet at idle/desktop use, and have the CPU, case and GPU fans only spin up during load (gaming) when I won't hear them anyway. My previous build had case fans always spinning at normal speed (use molex connectors).

I chose this Asus board because of the Fan Xpert 2 software, and 6 fan headers on the mobo itself (all 6 are PWM, 4 of them can do PWM or 3-pin control). Using the software I can tie the fan speeds (and whether they are powered on at all) to a temperature graph using % of the fan's speed. The speeds are tied to the CPU temperature, but you can easily find the relationship of CPU temp to other components if need be.

I like this approach as it occurs automatically and does not require buying a fan controller. I know there are fancy controllers with LCD screens that can be programmed to do this functionality rather than the motherboard, so that is an option.

So far I'm very happy with my case (Corsair 550D, 3x stock Corsair fans + 1x GELID Silent 12 PWM fan), mobo (Asus P8Z77-V Pro) and video card (Gigabyte Windforce 670 OC) for meeting my objectives. The only thing I have to change is assigning the fans on my NH-D14 heatsink to a different header so tehy can be voltage controlled, as they spin at 1200rpm right now which is clearly audible.