Airflow Questions Phanteks P400

[ScottAD]

I will be building a Ryzen PC soonish, maybe this weekend. Using the NZXT Kraken X61. Should I set the rad in push-pull? If so should I mount the push fans beneath the front IO panel? There are only two vents on the front panel at the top and the bottom. I would hate to waste fans that provide poor airflow.

My thought currently is to flip my PSU upside down and vent it out of the bottom. 140mm fan for pushing air out of the back
2x1400m pushing air up and out of the top, 280mm rad on the front in push-pull if possible.

I understand every case is different just wanting to collect opinions.

 

[Valantar]

Are you aiming for negative pressure? Because to my mind, that is what it looks like you'll get with your proposed setup. Even in push-pull, your rad is a significant impediment to airflow, so it will likely provide less air coming in than what's being exhausted by your three exhaust fans (all three of which are unobstructed?). That is, unless you run some overpowered fans at high rpms on the rad and everything else dead-slow. Which strikes me as odd.

As for front fan placement, I'd say that if you can fit the entire setup inside of the case (without fans mounted behind the front panel), do this. Fans mounted right behind the front panel will be obstructed by it, and they already have a radiator to contend with. Not to mention that you're limiting the free airflow path area behind the panel by having fans there. The difference might not be huge, but I'd veer on the safe side if you can fit all of it inside the case to begin with.

 

[ScottAD]

Are you aiming for negative pressure? Because to my mind, that is what it looks like you'll get with your proposed setup. Even in push-pull, your rad is a significant impediment to airflow, so it will likely provide less air coming in than what's being exhausted by your three exhaust fans (all three of which are unobstructed?). That is, unless you run some overpowered fans at high rpms on the rad and everything else dead-slow. Which strikes me as odd.

As for front fan placement, I'd say that if you can fit the entire setup inside of the case (without fans mounted behind the front panel), do this. Fans mounted right behind the front panel will be obstructed by it, and they already have a radiator to contend with. Not to mention that you're limiting the free airflow path area behind the panel by having fans there. The difference might not be huge, but I'd veer on the safe side if you can fit all of it inside the case to begin with.

I'd shoot for positive pressure preferably. I definitely don't want to suck in more dust etc. I will have to tinker with the radiator stack. I believe the rad sammich will fit in the case based on a YT video I watched. Maybe having just the rear as exhaust and filtering the tops as intakes would be best.

 

[monkeydelmagico]

Positioning radiators to put heat into the case is not ideal. Either don't put it on the front or completely reverse the airflow so it pushes the hot air out the front.

 

[Valantar]

Positioning radiators to put heat into the case is not ideal. Either don't put it on the front or completely reverse the airflow so it pushes the hot air out the front.

Actually with an open-air (not blower-style) GPU, it's better to have the CPU radiator as a front intake. Why? Because the GPU (which inevitably consumes far more power (and thus produces more heat) than the CPU) would otherwise significantly raise CPU temperatures. This video shows this quite clearly. On the other hand, the rather insignificant heat output of your average non-HEDT CPU will have no noticeable effect on GPU temperatures.

 

[monkeydelmagico]

Actually with an open-air (not blower-style) GPU, it's better to have the CPU radiator as a front intake. Why? Because the GPU (which inevitably consumes far more power (and thus produces more heat) than the CPU) would otherwise significantly raise CPU temperatures. This video shows this quite clearly. On the other hand, the rather insignificant heat output of your average non-HEDT CPU will have no noticeable effect on GPU temperatures.

Agreed. Would be good to know what case the OP is working with. If the rad can be top/back mounted would be the best scenario no?

 

[ScottAD]

Agreed. Would be good to know what case the OP is working with. If the rad can be top/back mounted would be the best scenario no?

Phanteks P400, top mounting is not possible with that case, not enough clearance with mobo.

I'm using the B350 Tomahawk from MSI

 

[Valantar]

My suggestion: the rad as a front intake in a push-pull config (no fans behind the front cover if it can be avoided), and two exhaust fans - one front and one top. Block off the second top fan slot if possible, and run the exhausts at lower speeds than the intakes. That should give you positive or neutral pressure, plenty of airflow. Three exhausts is unnecessary and makes negative pressure almost unavoidable. Place the PSU with the intake facing down, so that it takes in cool air and doesn't affect airflow for the rest of the case.

 

[ScottAD]

My suggestion: the rad as a front intake in a push-pull config (no fans behind the front cover if it can be avoided), and two exhaust fans - one front and one top. Block off the second top fan slot if possible, and run the exhausts at lower speeds than the intakes. That should give you positive or neutral pressure, plenty of airflow. Three exhausts is unnecessary and makes negative pressure almost unavoidable. Place the PSU with the intake facing down, so that it takes in cool air and doesn't affect airflow for the rest of the case.

Thank you, first time I've had to consider the use of a rad

 

[BonzaiDuck]

I will be building a Ryzen PC soonish, maybe this weekend. Using the NZXT Kraken X61. Should I set the rad in push-pull? If so should I mount the push fans beneath the front IO panel? There are only two vents on the front panel at the top and the bottom. I would hate to waste fans that provide poor airflow.

My thought currently is to flip my PSU upside down and vent it out of the bottom. 140mm fan for pushing air out of the back
2x1400m pushing air up and out of the top, 280mm rad on the front in push-pull if possible.

I understand every case is different just wanting to collect opinions.

But the PSU would have airflow in the opposite direction, if it had airflow at all. The 120mm fan in the PSU is pulling air and pushing it out the rear switch-panel PSU vent. The PSU will essentially be sucking air from the bottom of the case and forcing it out the panel vent, with no interaction with the case airflow. It would be a good idea to filter it. filter the PSU's 120mm fan.

The difficulty with 2x2x radiator fans is in finding room in the case. Are there drive cages that fit behind the radiator-fan assembly? Is there a case facie or outer door, which offers extension space forward of the chassis-front? The popular view is to put the radiator on the intake side, getting the coolest air from the case exterior. I happen to think that different airflow strategies make an exhaust radiator mount not measurably worse. Either way, you need ample airflow into and from the case.

 

[ScottAD]

But the PSU would have airflow in the opposite direction, if it had airflow at all. The 120mm fan in the PSU is pulling air and pushing it out the rear switch-panel PSU vent. The PSU will essentially be sucking air from the bottom of the case and forcing it out the panel vent, with no interaction with the case airflow. It would be a good idea to filter it. filter the PSU's 120mm fan.

The difficulty with 2x2x radiator fans is in finding room in the case. Are there drive cages that fit behind the radiator-fan assembly? Is there a case facie or outer door, which offers extension space forward of the chassis-front? The popular view is to put the radiator on the intake side, getting the coolest air from the case exterior. I happen to think that different airflow strategies make an exhaust radiator mount not measurably worse. Either way, you need ample airflow into and from the case.

The PSU lives in the shroud, I don't consider it part of the airflow mechanics I was considering. My venting out statement was incorrect, I apologize for that. I simply meant that because it is in the shroud it needs to be upside down so that it can vent out the back and get air from below. The PC will sit on a desk so airflow should not be an issue for the PSU.

The rad will be inside the case, I watched a fella fit the x61 in this case with push-pull.

https://youtu.be/oiMmiEbM3Ks

 

[BonzaiDuck]

On the PSU, I've deliberately done it either way, but if the air going into the 120mm intake for the PSU is coming from outside the case, I'd filter it. Flipping it the opposite way means, on the one hand, you have a leak in your pressurized case which nevertheless channels air across the PSU hot components in the direction intended. On the other hand, the air from inside the case should already be filtered. There's nothing wrong with doing it either way, I don't think.