Question Remove an exhaust fan?

[topgun505]

So in the process of seeing how all the fans will be set up in the new rig I encountered a possible issue.

The CPU is air cooled with a Noctua setup (one heat sink with 2 fans on it blowing to the rear). One rear exhaust fan as per normal. 2 exhaust fans on top and 3 intake fans on the front (but one of them has probably half of its airflow going into the lower PSU compartment).

The problem is the forward-most top exhaust fan is located just in front of the first CPU heat sink fan (the heat sink is only like 1-2" away from the top fans ... just really close together).

I'm wondering if that exhaust fan is going to 'steal' cold air coming in from the front intakes ... and thus it would be better to leave that fan off and just have one exhaust on top? That would leave around 2.5 fans blowing into the case and 2 fans exhausting which (feasibly) should amount to a positive pressure setup? Thoughts? (note, all fans are the same size, 120s).

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. For this instance please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
GPU:
Chassis:

The problem is the forward-most top exhaust fan is located just in front of the first CPU heat sink fan (the heat sink is only like 1-2" away from the top fans ... just really close together).
In instances like that, you don't populate the topmost top exhausting fan on the chassis that's located near the front panel's fan intake.

That would leave around 2.5 fans blowing into the case and 2 fans exhausting which (feasibly) should amount to a positive pressure setup?
I'm curious to see how you came to the number of 2.5.

 

[dev_cyberpunk]

The problem is the forward-most top exhaust fan is located just in front of the first CPU heat sink fan (the heat sink is only like 1-2" away from the top fans ... just really close together).

I'm wondering if that exhaust fan is going to 'steal' cold air coming in from the front intakes ... and thus it would be better to leave that fan off and just have one exhaust on top? That would leave around 2.5 fans blowing into the case and 2 fans exhausting which (feasibly) should amount to a positive pressure setup? Thoughts? (note, all fans are the same size, 120s).

It might because they seem to try to engineer them to be compatible with liquid cooling instead of pure air flow cooling. Problems I see is most don't have a solid panel under the board and other hole stamped in the case so the static pressure that should be there at the heat sink intake is not as great.

I find aluminium tape being helpful to block holes and establish air cooling zones and you can add or subtract if the cooling strategy doesn't work out.

There was a case manufacturer that went out of business in the US 20 years ago that I wished they were business because I haven't seen anyone build them like they did: swap-able panels (solid or with different fan configurations) the motherboard + card cage was on a sliding drawer, industrial casters instead of office furniture casters, and power supply on full towers could be either configured on top or on the bottom. They just don't make it like that I guess because they wouldn't have a wide profit margin compared to those $100-$200 that are $40-$60 cost of manufacturing.

 

[topgun505]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. For this instance please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
GPU:
Chassis:

The problem is the forward-most top exhaust fan is located just in front of the first CPU heat sink fan (the heat sink is only like 1-2" away from the top fans ... just really close together).
In instances like that, you don't populate the topmost top exhausting fan on the chassis that's located near the front panel's fan intake.

That would leave around 2.5 fans blowing into the case and 2 fans exhausting which (feasibly) should amount to a positive pressure setup?
I'm curious to see how you came to the number of 2.5.

core i9-14900kf
Noctua nh-u12a
Gigabyte aorus elite ax Z790
4x gskill trident z5 32GB
Gigabyte RTX 4080 super
Corsair icue 4000d airflow

If you look at the front from inside the case you can only see the top half of the bottom fan. The other half of the fan is blowing into the separated lower bay where the psu is.

 

[Rokinamerica]

Apologize if I missed it, but what are your currents temps?

 

[geofelt]

So in the process of seeing how all the fans will be set up in the new rig I encountered a possible issue.

The CPU is air cooled with a Noctua setup (one heat sink with 2 fans on it blowing to the rear). One rear exhaust fan as per normal. 2 exhaust fans on top and 3 intake fans on the front (but one of them has probably half of its airflow going into the lower PSU compartment).

The problem is the forward-most top exhaust fan is located just in front of the first CPU heat sink fan (the heat sink is only like 1-2" away from the top fans ... just really close together).

I'm wondering if that exhaust fan is going to 'steal' cold air coming in from the front intakes ... and thus it would be better to leave that fan off and just have one exhaust on top? That would leave around 2.5 fans blowing into the case and 2 fans exhausting which (feasibly) should amount to a positive pressure setup? Thoughts? (note, all fans are the same size, 120s).

You could be right.
It is easy enough to test. Just disconnect one or two of the top exhaust fans and see how you do.
Whatever cooling air comes in the front will exit SOMEWHERE.