Negative Pressure Setup?

[Ravendarat]

So Im wondering, how negatively would the cooling be affected on a PC with all fans in  a negative pressure layout. Ill have 2 360mm rads cooling a  5800x and either a 3080 or a 6800xt depending what I can get my hands on. I can obviously do the front rad fans as intakes and the tops as outtake, but that does hide the RGB of the front fans quite a bit. If I mount them also as outtake what kinda temp handicaps am I setting up for myself?

[Bombastinator]

46 minutes ago, Ravendarat said:

So Im wondering, how negatively would the cooling be affected on a PC with all fans in  a negative pressure layout. Ill have 2 360mm rads cooling a  5800x and either a 3080 or a 6800xt depending what I can get my hands on. I can obviously do the front rad fans as intakes and the tops as outtake, but that does hide the RGB of the front fans quite a bit. If I mount them also as outtake what kinda temp handicaps am I setting up for myself?

Heavy negative pressure is liked better than heavy positive pressure generally.  The issue is dust bunnies collect in weird places like cracks and whatnot.  I’ve heard the best possible setup is almost totally neutral with just the barest whisper of positive pressure.  Hard to arrange for though.  Negative pressure can be great if you’ve got really good control of case airflow.  I’ve heard of people doing heavy negative pressure and sealing all the cracks in their machine with electrical tape so air would only enter the way they wanted it to.  Pita to do maintenance  on of course because of all the tape.  As far as raw cooling goes ignoring dust, both heavy negative and heavy positive have the same problem.  The air may stay in the case longer than you want it to and heat up, and it may not move around very much, making for less cooling.

Edited June 10, 2021 by Bombastinator

[Ravendarat]

6 minutes ago, Bombastinator said:

Heavy negative pressure is liked better than heavy positive pressure generally.  The issue is dust bunnies collect in weird places like cracks and whatnot.  I’ve heard the best possible setup is almost totally neutral with just the barest whisper of positive pressure.  Hard to arrange for though.  Negative pressure can be great if you’ve got really good control of case airflow.  I’ve heard of people doing heavy negative pressure and sealing all the cracks in their machine with electrical tape so air would only enter the way they wanted it to.  Pita to do maintenance  on of course because of all the tape.  As far as raw cooling goes ignoring dust, both heavy negative and heavy positive have the same problem.  The air may stay in the case longer than you want it to and heat up, and it may not move around very much, making for less cooling.

Thanks, dust isnt a concern, im fine dusting weekly, maybe ill see if i can get something figured out to counteract hot spots/stale air

[Bombastinator]

4 minutes ago, Ravendarat said:

Thanks, dust isnt a concern, im fine dusting weekly, maybe ill see if i can get something figured out to counteract hot spots/stale air

If you’re willing to keep dust filters clear you may be best served by positive pressure. With positive pressure you get automatic control of airflow but the dust filters can fill up quickly, and depending on how fine they are you can still have buildup of fine particulate int the case.  Negative pressure makes for slower air generally so less total and smaller particulate.  The problem is you lose automatic control of airflow and dust bunnies can build up in places you can’t conveniently reach them. 

[LIGISTX]

1 hour ago, Ravendarat said:

So Im wondering, how negatively would the cooling be affected on a PC with all fans in  a negative pressure layout. Ill have 2 360mm rads cooling a  5800x and either a 3080 or a 6800xt depending what I can get my hands on. I can obviously do the front rad fans as intakes and the tops as outtake, but that does hide the RGB of the front fans quite a bit. If I mount them also as outtake what kinda temp handicaps am I setting up for myself?

Why would this affect RGB? You can put the fans on either side of the radiator, so if you want the RGB facing out he front panel, put them on the front of the rad pushing in. If you want the RGB on the inside of the case, put them on the back of the rad sucking in...

 

Don't put them all as exhaust, this will not work out well. But you can just flip the fans so they push or pull, depending on where your putting them and what you want...

[Ravendarat]

49 minutes ago, LIGISTX said:

Why would this affect RGB? You can put the fans on either side of the radiator, so if you want the RGB facing out he front panel, put them on the front of the rad pushing in. If you want the RGB on the inside of the case, put them on the back of the rad sucking in...

 

Don't put them all as exhaust, this will not work out well. But you can just flip the fans so they push or pull, depending on where your putting them and what you want...

The reason it matters is they are corsair LL fans so they only have the LED on one side, I want them lighting up the inside of the case so I want all fans on the inside of the rads not on the front. Realistically they are stupid lights so if its a bad idea I will just set one set as in and one as out. Its not that big of a deal, more just thinking outloud before I start. Im still waiting on tubing (6 weeks and counting corsair) and a gpu so Im not starting any time soon anyways

[Bombastinator]

3 minutes ago, Ravendarat said:

The reason it matters is they are corsair LL fans so they only have the LED on one side, I want them lighting up the inside of the case so I want all fans on the inside of the rads not on the front. Realistically they are stupid lights so if its a bad idea I will just set one set as in and one as out. Its not that big of a deal, more just thinking outloud before I start. Im still waiting on tubing (6 weeks and counting corsair) and a gpu so Im not starting any time soon anyways

Ah.  A love child type build.  Perhaps negative pressure and tape then.  Open loop does need a certain amount of maintainance though and you’d have to remove some of the tape to get into the case.  Hard call.  

[Ravendarat]

1 minute ago, Bombastinator said:

Ah.  A love child type build.  Perhaps negative pressure and tape then.  Open loop does need a certain amount of maintainance though and you’d have to remove some of the tape to get into the case.  Hard call.  

Lol ya, like its not a big deal, also not my first open loop system, might actually have another idea but ill have to play around with some things to figure out if it will work, stay tuned

[For Science!]

5 hours ago, Ravendarat said:

Lol ya, like its not a big deal, also not my first open loop system, might actually have another idea but ill have to play around with some things to figure out if it will work, stay tuned

In my system negative pressure outperforms positive/balanced pressure by almost 10 degrees fluid temperature. With watercooling one of the advantages is to directly exhaust the hot air through the radiators out of the case, if you are sending that air in, you have more work for the case fans to do.