airflow dilemma

[pauLoHSMF]

hello, got my new case and the x73 (360) AIO.

 

the problem is , how do i manage the airflow for positive pressure?

 

the case has 3x 140mm fans , initially mounted as 2 intake and 1 exhaust , but i will probably mount the AIO in the front , or maybe on top, haven't decided yet.

 

the problem is the AIO has 3x 120mm fans , so do i need to remove one of the 140s?

 

how do i deal with this? do i need to add or remove some fans to get the proper pressure? 

[Jae Tee]

PC airflow is all about common sense, as there is no 1 size fits all. I'm assuming the 3 120mm fans on your radiator will be in the front pushing in, so I would leave 1 140 for exhaust, and call it a day. However you may see something different, go with what you think is logical and don't be afraid to test. Also keep in mind air for you GPU.

[pauLoHSMF]

5 minutes ago, Jae Tee said:

PC airflow is all about common sense, as there is no 1 size fits all. I'm assuming the 3 120mm fans on your radiator will be in the front pushing in, so I would leave 1 140 for exhaust, and call it a day. However you may see something different, go with what you think is logical and don't be afraid to test. Also keep in mind air for you GPU.

i don't really have time nor want to spend hours and days mounting/dismounting and doing tests to see if temps change a few degrees.

 

i asked because i thought other people had this problem since i'm quite confused on which setup would be "optimal"

 

my initial plan is to put the aio in the front as intake but if i have clearance for ram i might mount it on top , leaving me..again , with confusion about what to put then as intake? and if i should put a fan in the rear also...oh god 

[Jae Tee]

4 minutes ago, pauLoHSMF said:

i don't really have time nor want to spend hours and days mounting/dismounting and doing tests to see if temps change a few degrees.

 

i asked because i thought other people had this problem since i'm quite confused on which setup would be "optimal"

 

my initial plan is to put the aio in the front as intake but if i have clearance for ram i might mount it on top , leaving me..again , with confusion about what to put then as intake? and if i should put a fan in the rear also...oh god 

So I'd suggest putting the aio in the front. But do not exhaust out of the top as that would kill airflow for most of your system. Front to back is your best option. 

[pauLoHSMF]

1 minute ago, Jae Tee said:

So I'd suggest putting the aio in the front. But do not exhaust out of the top as that would kill airflow for most of your system. Front to back is your best option. 

isn't that a low amount of exhaust compared to the front?

3x120 from the rad in front with just only 1x 140 exhaust at the rear? mhh

 

was thinking of putting 3x 140 intake in front and the rad on top as exhaust(3x120) + 1x 120 on the rear

[PriitM]

Water cooling and positive pressure is a logical combination: no dust and lower noise levels. 

The counter-intuitive part about this setup is: inside the case becomes a big hotspot. There are components that are designed for regular air cooling. Most notably VRMs. AIO-s do not have enough airflow (speed) to move the internal volume of air fast enough to cool those components. Doubly so in a pos. pressure situation.

 

Because you are gonna dust filter everything anyway, I would suggest you filter every single intake and put the AIO to exhaust mode. 

 

Heat related issues (thermal throtteling, possible hotspot components in hard to reach places that could fail faster etc) outweigh the benefit of a positive pressure set up.

 

EDIT: I would only put at max 2x140 (a single 140 at the bottom on the front) in front and 120 at rear. This is on the assumption your PSU is bottom mount. 

[Jae Tee]

1 minute ago, pauLoHSMF said:

isn't that a low amount of exhaust compared to the front?

3x120 from the rad in front with just only 1x 140 exhaust at the rear? mhh

   

Low exhaust is not going to be an issue. 

1 minute ago, pauLoHSMF said:

was thinking of putting 3x 140 intake in front and the rad on top as exhaust(3x120) + 1x 120 on the rear

This will cause most of the air to go from the front of your case to the top without cooling anything in between, which would be a waste. 

[PriitM]

29 minutes ago, Jae Tee said:

Low exhaust is not going to be an issue. 

This will cause most of the air to go from the front of your case to the top without cooling anything in between, which would be a waste. 

here is a simplified scheme of your situation: 3x120 pulling air out from the top, intakes on front and back. The front intake will take the shortest route possible, so not going over many of the hot components on the motherboard. Front intake contributes a little bit to cool the GPU, but mostly to get equilibrium of pressure/airflow inside the case. Rear intake will provide most of the airflow over the motherboard

 

Red zones are the biggest heat generators. VRMs will be cooled via the rear intake blowing on them and natural convection since they are close to the AIO. The biggest culprit of heat will be the GPU. If you dont have a blower type of GPU that exhaust directly out the case, you will exhaust into the case.

 

The area marked bright yellow is the dead zone of re-circulation. This is a little bit remedied by the front intake (if mounted low), but not much.

 

 I would put 1x140 at the bottom on the front and 140mm in the rear pushing hot GPU air away towards the front. This creates an airflow path that should, in theory, keep GPU re-circulation low and allow AIO low air speed to manage the total internal volume of air. 

 

If you really want to find out if it will work, you must find a radiator airflow calculator. I would say you should move the PC case internal volume of air in 2-3 seconds for optimal air flow and heat absorption.