# [SOLVED] Which one is worse?



## CATSr2 (Apr 7, 2012)

Hi there. I have a question on airflow. Is it bad to have a rear exhaust case fan on high and the front intake low, or is it bad to have the front intake high and the rear low? I ask this because I salvaged a 4 pin case fan and my motherboard is only 3 pin. If I plug it in right, it works, but only on high. And instead of buying one, I'm cheep and want to try to get this working first. Thank you in advance.


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## bassfisher6522 (Jul 22, 2012)

*Re: Which one is worse?*

For air cooling there are 3 types of Air Pressure setups. There is positive air pressure which means you have more clean air coming into the case then going out. There is negative air pressure which means you have more hot air exhausting the case. Then there is the balanced air pressure which means you have equal amounts of air flow coming in and out at the same time....which in my opinion is the best over all setup. Although it's been reported that some users get better cooling temps using either positive or negative air pressure setups. Remember case design has a lot to do with air flow, no matter how many fans one installs, if the case can't handle a smooth flow of air across the hardware efficiently then installing a bunch of case fans is utterly useless waste of time/labor and expense. 

As far as the 4pin plug using the 3pin header is ok...it's just missing the PWR (which is the 4th pin) to control the fan speed through the BIOS or some 3rd party software like Speedfan. It's just the nature of the beast. 

As an alternative, you could get a speedfan controller for $10 that you can manually adjust the speed of your fans...or just get a 4pin case fan for same $10.


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## CATSr2 (Apr 7, 2012)

Okay. Thank you for the info (never knew any of that till now) 

So should I try and place the 4 pin fan in the front of my case and track my temps to see what happens?


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## Rich-M (May 2, 2007)

*Re: Which one is worse?*

Yes as you do want the fans to be equal in speed as the other combinations spell trouble with either too much dust inside the case or too little cooling no matter how you look at it.


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## CATSr2 (Apr 7, 2012)

*Re: Which one is worse?*

Hmm. I guess I'll just monitor my temps, then switch the fans around, monitor again, and take my pick. 

Thanks for the info and help.


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