Is it better to have your exhaust fans on top or on the bacK?

Hello, I just ordered the Lian Li PC-2120 to upgrade my older Lian Li with the PSU on top. This new Lian Li that I ordered comes with 3 blowholes on top. Should I install exhaust or intake fans on top?

 

front and side - intake (bottom too)
rear and top - exhaust

usually that's best way

how to use fans in haf 912 case (just to see expample of airflow)
http://www.coolermaster-usa.com/landing/haf912/home.php?page=cooling

 

Heat rises so you get a little bit of free energy to the flow if you put them feeding out from the top.

 

Dont really matter as long as you have your heatsink setup blowing air out of 1 of your outlets(fan) the difference in temps regarding both types is negligible and side fans on a case dont do ****,they aint worth it in my testing in the past.

 

for me side fan cools down gpu alot.. and if u have cpu that have fan to blow from side to mb (like stock ones or c14 etc..) it's also help (providing cold air directly to cpu)
but it depend on where in side is mounted..

 

There is no one answer, it all depends on the layout of the case and the stuff inside it.

 

This.

 

Double post! Sorry.

 

Well, here's an old article on the question: http://tech.icrontic.com/article/pc_airflow_heat_cooling_guide/ . It's outdated, you might have read it already, but I'd like to have a theory to try out before going for something. I like the conclusion they came to: front+top gets the heat fastest according to them. So far I agree. But as the others said it depends always.

And here's another article debunking the myth that the vertical orientation gives the best cooling: http://www.pugetsystems.com/labs/articles/Vertical-vs-Horizontal-Case-Cooling-89 . It all comes to the inner layout of the case. The less "obstacles" (drive cages, cables..) you have between your fans and the mb/vga/whatever the better cooling you get.

 

As Lukc originally said.

More critical: Front intake. Back exhaust.
Less critical: Side intake. Top exhaust.

And for all four cases, the direction should not be reversed. A top fan should never serve as an intake. It negates the most simple physical aspects of hot air and general case airflow.

This isn't opinion; it's fact and it's been shown by enough guides and reviews that you'd think people would have a more consenual opinion by now. Yes, it can depend on case layout but only in cases in which the layout diverts very far from standard layout.

 

shimyns, convection while a strong concept in thought, simply does not generate the results necessary to play a discernible role in a typical chassis. That isn't opinion it's a fact. Using the rear and top fans as intake-you can do. Let him try out and see what's best for himself.

 

The way mine is set up is front = intake, side = intake, top = exhaust, rear = exhaust. Heat always rises so defiantly make the top fan exhaust. The key is to build an even amount of intake and exhaust pressure to be sufficient.

 

So where should I mount my radiator to? The rear exhaust or the top exhaust? And would having both rear and top exhaust provide better cooling than just one exhaust?

 

Whichever has the highest airflow.
My radiator has its own dedicated 250mm fan.

You need about the same CFM going out as coming in the case.

 

agreed there.

on my old 5850x2 setup, i replaced both cards with zalman vf2000 gpu coolers.

having a side fan reduced the temps of the top card by 25C compared to running a side panel with a solid perspex window. the coolers were open heatsink (no shroud), which does kinda help as well.