Case Pressure

[skitz]

Hey guys,

 

I have heard in a number of videos people talking about internal case pressure, and positive and negative pressure depending on where and # of inlets and outlets in a case. Can anyone explain to me factors that need to be considered when building, and positive and negative pressure as well as how to achieve these things.

 

Thanks

[jonasa97]

Negative pressure = more exausts than intakes (in terms of CFM/   cubic feet of air/minute)

Positive pressure = more intakes than exausts (in  terms of CFM)

Basically with negative pressure your PC case will be a vacuum cleaner and therefore intake more dust as far as I'm concerned.

[FloRolf]

Hey guys,

 

I have heard in a number of videos people talking about internal case pressure, and positive and negative pressure depending on where and # of inlets and outlets in a case. Can anyone explain to me factors that need to be considered when building, and positive and negative pressure as well as how to achieve these things.

 

Thanks

 

the only real thing to consider is, that you have more intake than exhaust fans and all the inlets filtered. This prevents dust to get in your system.

If you would have more exhaust, dusty air would be sucked into the case through some holes here and there.

[BoomLiam]

This picture is a really good illustration of positive and negative air pressure in computer cases: http://files.tested.com/photos/2013/02/08/44527-ss_airflow.png

 

It is really only something you need to consider if your cases has fan filters and the main thing having positive air pressure does (as indicated in the picture) is to slow down the build up of dust in your case. But if you have no fan filters, then dust is going to get in either way (even faster with positive airflow) so my tip would be, get fan filters and have more fans blowing in than out.

[Hyydrah]

Negative pressure = more exausts than intakes (in terms of CFM/   cubic feet of air/minute)

Positive pressure = more intakes than exausts (in  terms of CFM)

Basically with negative pressure your PC case will be a vacuum cleaner and therefore intake more dust as far as I'm concerned.

I don't know if you mean "more" as in more fans, because fan size, speed, etc. plays a role, not just quantity

[jonasa97]

I don't know if you mean "more" as in more fans, because fan size, speed, etc. plays a role, not just quantity.

Read the whole post -_- I mentioned to measure it in terms of CFM.

[Hyydrah]

Read the whole post -_- I mentioned to measure it in terms of CFM.

Oops, missed that. CFM isn't the whole story though, hopefully you knew that

[jonasa97]

Oops, missed that. CFM isn't the whole story though, you know that right?

Only if you're trying to blow the air through a very small hole, you do need static pressure if that's the point you're trying to make. However I think the OP get's the point :P.

[Lays]

quick question, I have  1 230mm Intake, a 200mm exhaust on my sidepanel, 120mm rear exhaust, and 3 120mm intake fans on top, 2 of which are on my rad.  

 

Do I have to much exhaust? 

[jonasa97]

quick question, I have  1 230mm Intake, a 200mm exhaust on my sidepanel, 120mm rear exhaust, and 3 120mm intake fans on top, 2 of which are on my rad.  

 

Do I have to much exhaust? 

 As long as The air is nicely filtered at the intakes, there's nothing bad about negative pressure. I'd recommend resetting up the whole thing the following way: keep the 230mm intake, the sidepanel should intake air to blow on to your GPU, and then setup the 3 top fans as exausts. It just works better with the physics: hot molecules go up. Therefore setting up your top fans as intakes might affect the temperatures :) hope this helped.

[Lays]

 As long as The air is nicely filtered at the intakes, there's nothing bad about negative pressure. I'd recommend resetting up the whole thing the following way: keep the 230mm intake, the sidepanel should intake air to blow on to your GPU, and then setup the 3 top fans as exausts. It just works better with the physics: hot molecules go up. Therefore setting up your top fans as intakes might affect the temperatures :) hope this helped.

 

 

Blowing hot air through my rad is gonna increase temps won't it?  And the 200m side as an intake doesn't help, I switched it recently and dropped temps by 5 celsius, hot air was being stuck inbetween the GPU's and not being removed.

[Warcony]

Blowing hot air through my rad is gonna increase temps won't it?  And the 200m side as an intake doesn't help, I switched it recently and dropped temps by 5 celsius, hot air was being stuck inbetween the GPU's and not being removed.

 

Depends on what type of cooling system is installed on your GPU. If it has a blower fan then setting the sidepanel fan as intake won't be very effective.  It also depends on how good the airflow is through your case and if there's a lot of stuff in the way.  I would run the top Rad as intake, rear and front as exhaust and sidepanel as intake or exhaust, whatever gives you the best results overall

[jonasa97]

Blowing hot air through my rad is gonna increase temps won't it?  And the 200m side as an intake doesn't help, I switched it recently and dropped temps by 5 celsius, hot air was being stuck inbetween the GPU's and not being removed.

The air was most probably stuck because the top fans pushed it back. Try setting up the fans as I recommended as it will generally improve the airflow and prevent air from getting stuck. All the fans need to work together in a PC case, not against each other.