Tips on case airflow / fan placement

[jvmunhoz]

I decided it was finally time to have a decent airflow since I changed my water-cooler for a Noctua NH-D15S a few months ago.

 

So I bought 6 Noctua NF-A14 PWM for my Corsair 750D Case and 2 Noctua NF-A15 HS-PWM for the Noctua NH-D15S. But I was wandering what is the best placement for them. My idea would be something like this:

 

 

The front fans are intake.

 

The bottom one is intake to bring some more cool air into the GPU (?)

 

The two NH-D15S fans are also intake.

 

The first top fan is also intake, to bring some cool air into the memory slots and in front of the NH-D15S (?)

 

The second top fan is outtake, to take some of the hot air created by the the NH-D15S out of the case (?)

 

The rear fan is also outtake, to remove the hot air created by the NH-D15S out of the case

 

 

Does that make sense? Any tips on other types of placemente?

 

Thanks in advance!

 

Full PC spec here

 

[Senzelian]

Two front fans and one fan in the back are enough. The rest are most likely just overkill and won't help you in any way.

[freeagent]

Looking at what you have, I would probably run it that way too.

[LogicalDrm]

Have both top fans as exhaust. You can set them to spin slower if you fear that D15S isn't getting enough air.

[Wolololo]

On 4/8/2020 at 1:18 AM, LogicalDrm said:

Have both top fans as exhaust. You can set them to spin slower if you fear that D15S isn't getting enough air.

I second this. But adding to it a bit, I'd change the exhaust to 120mms if you can afford to. Also, if you hadn't done this already. clean out the case too

[LogicalDrm]

6 hours ago, Wolololo said:

I second this. But adding to it a bit, I'd change the exhaust to 120mms if you can afford to. Also, if you hadn't done this already. clean out the case too

Why though?

[Wolololo]

3 hours ago, LogicalDrm said:

Why though?

In the parts list that the OP posted, all of the fans inside the case were 140mm, so there'd be negative pressure in the case. Typically, I think it's best to go with the positive pressure setup (less dust and whatnot), so I suggested the 120mm as exhaust. I'm aware you can change the fan curve and set the fans on a set rpm, but I'd just invest in some 120mm fans instead. Makes things easy.

[LogicalDrm]

2 hours ago, Wolololo said:

In the parts list that the OP posted, all of the fans inside the case were 140mm, so there'd be negative pressure in the case. Typically, I think it's best to go with the positive pressure setup (less dust and whatnot), so I suggested the 120mm as exhaust. I'm aware you can change the fan curve and set the fans on a set rpm, but I'd just invest in some 120mm fans instead. Makes things easy.

So the logic is that 120mm would have less CFM. Wouldn't even cheaper and easier to use only two exhausts? As they already bought fans?

[jvmunhoz]

On 4/7/2020 at 1:18 PM, LogicalDrm said:

Have both top fans as exhaust. You can set them to spin slower if you fear that D15S isn't getting enough air.

But how much slower? 20% slower, 30% slower...? Any tips on this matter?

6 hours ago, Wolololo said:

In the parts list that the OP posted, all of the fans inside the case were 140mm, so there'd be negative pressure in the case. Typically, I think it's best to go with the positive pressure setup (less dust and whatnot), so I suggested the 120mm as exhaust. I'm aware you can change the fan curve and set the fans on a set rpm, but I'd just invest in some 120mm fans instead. Makes things easy.

One of the other reasons I thought for having one of the top fans as intake is for positive pressure. But I gotta admit I'm not certain exactly how that would affect positive pressure, since what I know is basically positive pressure = more intake than exhaust

3 hours ago, LogicalDrm said:

So the logic is that 120mm would have less CFM. Wouldn't even cheaper and easier to use only two exhausts? As they already bought fans?

Yep, already bought the fans, it will have to be the 140mm.

 

PS: I'll definitely clean the case, I'm just finishing some RAM OC, then I'll proceed in changing the case fans

[LogicalDrm]

6 minutes ago, jvmunhoz said:

But how much slower? 20% slower, 30% slower...? Any tips on this matter?

Considering that intakes have stuff in front of them and exhaust don't, I would say 50% lower. Since you are using all same fans, the calculations are bit easier to do. Its 140cfm per fan. So without anything in front of them, its neutral pressure for 3 to 3. Considering that there will be stuff in front of 2x front ones, and one has HDD cage also in front of it. Lets say front panel takes 20% off, and HDD cage another 10%. So its 420cfm total, minus 70. Intake being something like 350cfm total, exhaust at 50% speeds 210cfm. Ofc, this is only theoretical and you will need to monitor dust accumulation to make sure things are correct.

[jvmunhoz]

9 hours ago, LogicalDrm said:

Considering that intakes have stuff in front of them and exhaust don't, I would say 50% lower. Since you are using all same fans, the calculations are bit easier to do. Its 140cfm per fan. So without anything in front of them, its neutral pressure for 3 to 3. Considering that there will be stuff in front of 2x front ones, and one has HDD cage also in front of it. Lets say front panel takes 20% off, and HDD cage another 10%. So its 420cfm total, minus 70. Intake being something like 350cfm total, exhaust at 50% speeds 210cfm. Ofc, this is only theoretical and you will need to monitor dust accumulation to make sure things are correct.

Why have both top fans as exhaust then? Not meaning to be rude, I'd like to understand.

 

Wouldn't have one of them as intake fix all of this?

[LogicalDrm]

18 minutes ago, jvmunhoz said:

Why have both top fans as exhaust then? Not meaning to be rude, I'd like to understand.

 

Wouldn't have one of them as intake fix all of this?

Because having one as intake and another as exhaust you will be circulating air between those two. They won't be so powerful that it would be beneficial to have two different orientation fans so close to each other.

[Wolololo]

On 4/12/2020 at 5:22 PM, LogicalDrm said:

So the logic is that 120mm would have less CFM. Wouldn't even cheaper and easier to use only two exhausts? As they already bought fans?

Well, yes of course you can do that too