Quick question RE: Top and side mount fans

Linwig · 2 Jul 2008 at 14:38

Hi guys, very quick question. Should a fan on the top of a case be pushing air up out of the case, and likewise a 120mm fan by the graphics card, should the fan be pushing air out, or blowing onto the graphics card? Thanks

Firestar_3x · 2 Jul 2008 at 14:41

Hot air rises so fans on the top of the case should be sucking the hot air out.

I would have the GFX fan blowing air onto the cooler.

Greebo · 2 Jul 2008 at 14:41

General idea is to have a flow of cool air running through the case. If you don't have a front fan I would have the side fan on in and the top fan on out (heat rises)

That way the cooler on the graphics card will be getting cool air and there will be a nice flow through the rest of your case and then out through the top.

Linwig · 2 Jul 2008 at 14:56

Thanks for your thoughts guys, I am thinking about getting an Antec 300 which has 120mm fans, one on the top and one on the back. Just deciding if I need to get 3 extra fans (2 at the front and 1 at the side) and which way they should be facing. Cheers

Firestar_3x · 2 Jul 2008 at 14:59

On my case (Lian-Li PC-75) i have the front two fans blowing air into the case past the HDD rack, air flow goes through the case and into the two extraction fans at the mid back of the case, then i have an extraction fan in the PSU and one on the top of the case, Watercooling rads are mounted outside.

Oh almost forgot i also have two 80mm extraction fans above the PSU but i'm not using them.

Due to whats giving out heat in my case i have less air being pushed in than being sucked out.

Pneumonic · 2 Jul 2008 at 15:09

Front / Side = In
Top / Rear = Out

Always more In than Out..

Firestar_3x · 2 Jul 2008 at 15:16

Depends, if you have a negative pressure setup, like mine, you will suck in more dust but you will also get more consistant airflow through the case.

If you filter the air coming in and have a well built case then dust isn't really that much of an issue, its all down to trail and error, both positive and negative pressure setups have up and downsides.

I do suffer from blocked up air intakes every few months but with silent intake and outake fans combined with a very large case i want the entire inside of the case to be at a consistent temp.

Pneumonic · 2 Jul 2008 at 15:20

Indeed it depends a lot on your case / componants and what is generating the heat.. and should be a lot of trial and error as to what works best..

but in general have always used a more in than out approach finds it gives better temperatures

WJA96 · 2 Jul 2008 at 16:13

Some systems are set up to run pressurized - the Lian Li PC-S80 for example has three 120mm fans and they all blow inwards. The air escapes down channels in the sides of the case. Very quiet, and very cool.