The Dreaded Positive vs Negative Air Pressure Cooling Debate

[Dubesta11]

What do you think is the best and why?

 

Edit: Added swimming pool

[TheSLSAMG]

I honestly just put fans in my case, front and bottom blowing in and rear and top blowing out.

[MegaDave91]

Slightly positive is best

[Creiger]

I have 5 blowing total on the back/side/bottom/front, and then 2 blowing out the top. Works well enough, even in hot rooms.

[AlexWalters08]

Positive, because it reduces the amount of dust that gets into the case. Also this is my 100th post to a expect you to like it and congratulate me  . (I am just kidding about everything after the first sentence)

[blackadder]

I clean twice a month so postive isn't a big deal.

[Dabombinable]

What do you think is the best and why?

Positive pressure is supposed to prevent dust from being sucked into the computer, Negative pressure means that dust will get sucked in through every little gap in the case. Though if you've got very fine dust in your house you'll still get dust inside your rig even with filters. I recently cleaned my rig out and it was as if the dust had been sifted it was that fine.

[MegaDave91]

Positive, because it reduces the amount of dust that gets into the case. Also this is my 100th post to a expect you to like it and congratulate me  . (I am just kidding about everything after the first sentence)

It doesn't reduce dust entering the case from official airways any more than negative pressure. It's how it's managed, so to speak, once it's in the case. 

[Trik'Stari]

I prefer the intelligent option. Laminar flow.

 

As much in, and as much out, as possible.

[Dabombinable]

It doesn't reduce dust entering the case any more than negative pressure. It's how it's managed, so to speak, once it's in the case. 

If your case is airtight and has a very fine filter behind the standard filters its actually possible to have next to no dust in your rig after several years use with positive pressure..

[MegaDave91]

If your case is airtight and has a very fine filter behind the standard filters its actually possible to have next to no dust in your rig after several years use with positive pressure..

Hell, why have any fans at all if intake is going to be that restricting?

 

The DataVac electric duster is invaluable and should be in every PC owner's arsenal. I can't think of a reason why a home PC should go even a year, let alone several without being cleaned.

[Dabombinable]

Hell, why have any fans at all if intake is going to be that restricting?

They'll still suck in plenty of air.

[Godlygamer23]

You want slightly positive pressure to reduce dust build up.

[Dubesta11]

I prefer the intelligent option. Laminar flow.

 

As much in, and as much out, as possible.

 

But that doesn't really answer the question. If you have space for 2 fans intake and 3 exhast, do you fill all the slots? Or 2 intake and 1 ex hast?

 

I suppose you like the Lanboy Air

 

[Trik'Stari]

But that doesn't really answer the question. If you have space for 2 fans intake and 3 exhast, do you fill all the slots? Or 2 intake and 1 ex hast?

 

I suppose you like the Lanboy Air

 

-snip

Currently running in an Air 540. three 120's in the front running off of the PSU (so full blast) and then I've got a 280mm rad in push/pull on the top (exhaust), with a single 140 in the rear (exhaust). The fans at the top are set to whatever "normal" is in the BIOS.

 

If you only have 2 intake and 3 exhaust, step down the exhaust fans a bit and up the intake a bit.

[dfsdfgfkjsefoiqzemnd]

Slightly positive is best to avoid dust, slightly negative is said to provide lower temperatures.

 

I had plenty of fan options in my case so I went for both positive and negative.  Under normal use I have slightly positive pressure, but when the PC gets hot (CPU over 50°C) extra fans kick in and the pressure becomes slightly negative. 

When it gets really hot (CPU beyond 60°C, which I have yet to see happen even during benchmarks), all the fans max out and I don't care what pressure it is anymore, At that point I just let it go for the full hurricane inside the case.

[ThomasD]

Cooling can be accomplished with either positive or negative pressure.  Better cooling is accomplished by moving a higher volume of air - be it negative or positive. 

 

Filtered positive pressure is for dust reduction.

 

I tend to think that negative pressure will yield the better air flow - since the air itself will find the path of least resistance.

 

But I also suspect that any benefit of ideal airflow will be quickly reduced or eliminated if any significant amount of dust is allowed to build up.

 

So I usually shoot for positive pressure, not because I think it gives the most efficient cooling, but because it is the better way to keep the interior clean (and I hate cleaning PCs.)