# intake/output fans set up



## Red Rover (Mar 17, 2011)

Is there a guideline to which fans should be intake/output (other than the obvious Front "in" and Back "out". 

My new case is a Thermaltake Dokker with two fan mounts on top and one on the side (beside the normal lower front and top rear).

I was thinking top rear for exhaust, top front for intake, side for intake. Common sense tells me heat rises so one top should be exhaust but only the front and side as intake, is that enough? 

I haven't read anywhere there is a set pattern for this type of thing. Maybe I'm missing something. I'm not OCing or anything crazy and only running a Core2Duo, but the more ventilation the better, right?


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## WereBo (Apr 5, 2008)

Hi Red Rover :wave:

You're right about about the front/back/top fans, but the side-fan is a bit more 'tricky' - Some cases are cooler with the side-fan as intake, whereas t'others are better with it as exhaust - There's also some instances where the case is cooler, without a side-fan at all









It's to do with the smooth airflow from front-to-back and how the side-fan interrupts or enhances that flow, cables, mobo components/cards etc. all affect it, so it's mainly a matter of trial-an'-error for individual cases - All you can do is try it one way for a couple of days, then reverse the fan and see if there's any improvement in the temps.

I hope that helps :grin:

Also, the more fans you have, the more noise there is - What temps are you getting from your CPU and GPU?


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## ickymay (Jan 6, 2010)

ide say ventilation no but airflow yes :wink:

When building systems my rule of thumb is to create the smoothest airflow path possible so opposing fans from 90 deg angles are often discouraged, but are sometimes necessary to increase internal air pressure, and front to back or front to top and back can work, but the most important factor is to make sure there is a slightly higher air pressure inside the case than outside so that expulsion of hotter air is always happening :idea:

I also try to use the minimum number of fans with maximum diameter for quietness sake, and for CPU I really like fan systems which use a front to back facing fan rather than "top down" , for example the Freezer 64 Pro PWM from Arctic Cooling :smile:


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## Red Rover (Mar 17, 2011)

Great feedback, thanks! As I am still building the rig WereBo I don't know temps yet, I was just thinking about installing everything now. 
I totally get the airflow concept and that makes total sense. I see where a side fan would disrupt that. I do have a cpu cooler (Cooler Master Hyper 212 Plus Universal CPU Cooler) and I am guessing that can be positioned either way, so front to back makes complete sense. 
I think I'll pass on the side fan for now, see how the temps go. Running 5 fans may also be a bit of overkill, like I said it's not wired for OC or anything crazy. 80% of the time will be basic web stuff, the other 20% PS and Vegas. 
All fans in the case are 120mm WereBo, I did check for the quietest ones or at least mentioned that on the box. Not too worried about absolute quiet, plus the old adage if you can hear it you know it's working. 
I think I'll start with larger cfm up front incoming, and lower cfm's in the back and tops outgoing to see how things work and check temps. 
I'll pop back and update to let you know.
Thanks!


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## WereBo (Apr 5, 2008)

Once you've got it up an' running, '*Speedfan*' is a handy little utility than displays your temp(s) in the system-tray - It sometimes needs 'calibrating' though, I've had some PC's where it's spot-on accurate, but others have had a 5-6C difference.

An accurate system-info/benchmark is '*PC Wizard 2010*', it'll tell you nearly everything about everything inside the case, including the various temps (accurately) and it's free :grin:


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## Red Rover (Mar 17, 2011)

Thanks WereBo! I have all of them installed. I had to remove the top rear fan since it wouldn't fit with the cpu cooler unit. 
Everything looks good so far, I did see once everything was in the case that the side fan would provide direct air to the psu and vid card. The height of the vid card keeps most of the air between it and the psu. I'm going to boot up tomorrow with that set up and see how it goes. 
Will advise.


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