Push/Pull question

[mattgal]

Hi

I have a Xigmatek Balder heatsink and would like to put it on push pull.

Now i have 2 fans available, the Xigmatek Fan (89CFM) and a Scythe (1200RPM 68CFM from OCUK).

Which would be on push and pull?

Thanks

 

[Hagar]

I would use two equal fans, if you push 89cfm into a space which is being exhausted at 68cfm you will have an excess pressure in between the fans. Similarly the 89cfm exhaust fan will pull air faster than the 68cfm can push it, tending towards a zone of low pressure air in the middle. This will not actually occur as air will be pulled in from the sides.

The other problem may be noise as the two inequal rpm will interact and you may end up with a pulsation going up and down in volume.

 

[TheCenturion]

I would have higher cfm pulling, lower pushing

 

[mattgal]

what if they are the other way round? (as they accidentally are right now) will it decrease performance? because according to my thinking (very reliable ) if only 1 fan is pushing air and no fans are sucking it it, performance would be decreased compared to "at least" 70cfm of pulling air.