Phanteks P400S

[knight_40k]

So I just pulled the trigger on a P400S Tempered Glass and while I wait for it to arrive I would like to know the best orientation for fan layout as I am about to order some RGB ones. What is the best fan combination of 120/140mm or does it matter? I am asking because I want to make the most of its cooling potential and hopefully not create negative air pressure.

 

According to the Phanteks website

120mm (3 front, 2 top, 1 rear)

140mm (2 front and 2 top)

 

So my question is, should I put dual 140mm at the top or 120mm at the top so they match with the single 120mm rear? Then what about 120mm vs 140mm at the front? Or just use 140mm wherever possible?

 

Thanks in advance.

[Colin Donoghue]

140s where ever possible slower fans speeds needed for the same cooling

[Zyndo]

2 minutes ago, knight_40k said:

What is the best fan combination of 120/140mm or does it matter? I am asking because I want to make the most of its cooling potential and hopefully not create negative air pressure

Pressure is denoted by air flow, not by fan count. You could have 1 120mm intake at the front running 2000 RPM and 3x120mm exhaust elsewhere running at 400RPM and still be left with positive pressure.

 

3 minutes ago, knight_40k said:

So my question is, should I put dual 140mm at the top or 120mm at the top so they match with the single 120mm rear? Then what about 120mm vs 140mm at the front? Or just use 140mm wherever possible

Depends entirely on what kind of aesthetic you're looking for and what funds you have. You could go with 3x120 in the front as intake, with 120 rear and 2x120 top as exhaust and end up with perfectly neutral pressure (or turn those front fans up a tad to bring it up to positive pressure if you wish). You don't need nearly that many fans though. You could go with whatever you want really. 2-3 fans is the sweet spot for cooling performance. beyond that you don't really see any temperature benefits at all for most normal systems.

[RadiatingLight]

12 minutes ago, Zyndo said:

Pressure is denoted by air flow, not by fan count. You could have 1 120mm intake at the front running 2000 RPM and 3x120mm exhaust elsewhere running at 400RPM and still be left with positive pressure.

Kinda.

if only airflow scaled linearly with RPM

[Zyndo]

6 minutes ago, RadiatingLight said:

Kinda.

if only airflow scaled linearly with RPM

I'm unsure if it it does or not.... hence why i 4x'd the RPM even though 3x the fan count. I'm unsure of the exact math but it should still work out in my arguments favor. If you have something useful to add to the OP's request for assistance then that's good. If you could even provide exact corrections/maths for my hypothetical numbers then great. If you're here just to stir the pot please head back to reddit.

[RadiatingLight]

4 minutes ago, Zyndo said:

I'm aware it does not.... hence why i 4x'd the RPM even though 3x the fan count. I'm unsure of the exact math but it should still work out in my arguments favor. If you have something useful to add to the OP's request for assistance then that's good. If you could even provide exact corrections/maths for my hypothetical numbers then great. If you're here just to stir the pot please head back to reddit.

K

[knight_40k]

20 minutes ago, Zyndo said:

Pressure is denoted by air flow, not by fan count. You could have 1 120mm intake at the front running 2000 RPM and 3x120mm exhaust elsewhere running at 400RPM and still be left with positive pressure.

So as long as air is coming in faster than being exhausted or if air is coming and going at the same rate I should be ok?

[Zyndo]

4 minutes ago, knight_40k said:

So as long as air is coming in faster than being exhausted or if air is coming and going at the same rate I should be ok?

if your desired goal is to have positive pressure or neutral pressure (what you're describing here) then yes that would be okay. negative pressure isn't as bad as everyone would make it out to be, it merely results in a bit more dust buildup over time (compared against a setup with filtered intakes and positive pressure). Negative air pressure actually results in slightly lower short term temperatures than positive pressure (conditions which eventually are rendered irrelevant due to dust build-up on components). But there is nothing inherently evil about negative pressure.