[SOLVED] Optimizing airflow in my Corsair 750D case

[stravencroft]

My system

As of writing I'm using a Corsair 750D Obsidian case with a the airflow front panel. Initially I had 4 AF140L's but I replaced all with 4 Noctura NF-P14's of the 3 pin 1200 variety. I replaced my aged cooler with a Noctua NH-DH15S. I had mounted a Noctua NF-P12 on the bottom but after some thinking removed it due to the amount of extension cables I was to get it into a free header (I picked up a Sata power converter later).

I have 2 NF-P4S as intake in the front. No room for a third fan on this case sadly so went with 140 over 120.
DH15S .chromax running with just the included single chromax PWM fan for ram access and better clearance.
I have 1 NF-P4S as exhaust next to the DH15S
I have 2 NF-P4S as additional exhaust above the DH15S mounted on the top of the case.
I had the 1 NF-P12 on the bottom but took it off for the moment as it actually seemed to make temps worse when I ran it. All I can mount is a 120 on this area anyway.

I've also a 3080 generating some heat and I think the two top P14s as exhaust are helping drive down temps.

I bought several of the low noise adapters to assist with noise once I figure out a good airflow setup.

Everything I seem to come across emphasizes positive airflow and I appear to have negative airflow with my exhaust fans. I was thinking of just taking off one of the two top exhaust fans and then maybe I'd see an improvement?

What could I optimize here?

 

[Gam3r01]

Positive vs Negative airflow is really not as important as people make it out to be, your setup sounds fine as is unless you are having some sort of issues?
The low noise adapters are going to make your airflow worse, all they do is slow down the fans so you are trading cooling for acoustics.

 

[stravencroft]

Should I replace all my 3 pin case fans for 4 pin PWM fans or go for the higher 1500 RPM variants? Wouldn't that be more efficient although somewhat expensive? I was trying to strike the sweet spot for not overly loud but good airflow.

 

[Gam3r01]

Replacing fans is just going to be throwing money away.
Does your motherboard have an option for voltage control on the 3 pin fan headers?

 

[stravencroft]

I'm not sure. I don't think there's anything physically on the board but maybe in the BIOS? The board is an ASROCK Z270M Extreme 4.
I know there are voltage controls in UEFI but I've never messed with them as I don't know enough to be comfortable making any changes.

In any event all my fan headers as far as I can tell are 4 pin headers. This was something I neglected to observe before I started ordering new fans. I was advised that it didn't matter as much for the case fans to be 4 pin as opposed to making sure the cpu fan was. Once I did some reading however I started to have some doubts which is why I'm posting. I've already threw away over 40 dollars on additional AF 140L fans before realizing I should have gone with P14's before now realizing maybe I should have purchased the 1500 RPM 4 pin variants instead. Going forward I'm trying to figure out what would be critical to change and what I can live with even if it is not ultra optimal.

 

[Gam3r01]

You can scroll down to the ASRock section here https://www.tweaktown.com/guides/8245/fan-control-guide-intel-z270-motherboard-edition/index.html, it looks as though you can control the speeds of 3 pin fans depending what header they are plugged into via DC voltage control.

 

[stravencroft]

I'm guessing that's part of how the FAN-tastic tuning works. Doesn't always seem to give me the best values to run my fans though usually always set them all to performance or 70 percent except the cpu which I leave on standard or 62.

I had thought about putting them all on full speed but that seems like it'd kill the bearings quick, Any good third party software you can recommend?