[SOLVED] Would it be of any benefit to add fans at the bottom of my case?

[emitfudd]

I have some extra 120mm fans and am wondering if it would be worth installing one or two at the bottom of my case as intake. I already have good airflow with the following setup.

Corsair 780T case with 2 140mm fans at the front as intake. 1 140mm fan at rear as exhaust. 360mm AIO mounted at top of case as exhaust. The bottom of the case has removable dust filters and can draw in fresh air passively.

The inside of my case is gutted with no drive bays or anything impeding airflow. By my math my case has negative pressure. 480mm worth of fans set to exhaust and 280mm worth of fans set to intake. Theoretically this should be sucking in quite a bit of air from the vents at the bottom of the case. Will it help much to pull in more air with one or two 120mm fans down there?

I don't have any overheating issues. My GPU has never exceeded 65C and the CPU has max spikes of 76C while gaming.

Ryzen 5900X CPU
MSI 3080 Gaming Z Trio GPU
Asus Crosshair VIII Dark Hero motherboard
G. Skill Trident Z Neo 32GB (2x16) 3600 CL16 RAM
Samsung 980 Pro 1GB x 2
Thermaltake Water 3.0 Ultimate AIO
Seasonic Prime Titanium 850W PSU

 

[tennis2]

By my math my case has negative pressure. 480mm worth of fans set to exhaust and 280mm worth of fans set to intake.

Adding up length isn't really a good way to do the math. CFM is better, but you need to take ACUTAL fan speed into consideration. Also, the static pressure of the AIO will prevent the AIO fans from reaching their maximum CFM potential (this CFM reduction also is not linear compared to fan speed, so it's complicated)

My GPU has never exceeded 65C and the CPU has max spikes of 76C while gaming.

Important to note fan speeds since we're really talking about noise reduction at this point.

I don't have any overheating issues. My GPU has never exceeded 65C and the CPU has max spikes of 76C while gaming.

Probably leave well-enough alone.

 

[emitfudd]

Adding up length isn't really a good way to do the math. CFM is better, but you need to take ACUTAL fan speed into consideration. Also, the static pressure of the AIO will prevent the AIO fans from reaching their maximum CFM potential (this CFM reduction also is not linear compared to fan speed, so it's complicated)

Important to note fan speeds since we're really talking about noise reduction at this point.


Probably leave well-enough alone.

Thanks for the info. I read a couple of articles after posting this that said bottom intake fans will help the GPU run cooler but not do much for the CPU. If anything, I was hoping to get the CPU down a few degrees. Probably right about leaving well enough alone.

 

[tennis2]

To lower CPU temps in a significant fashion, you'd want to put the AIO in the front as intake so it's getting fresh/cold air instead of the air inside the case that was pre-heated by the GPU.

Of course, that pumps CPU heat into the case, so then a bottom intake would help the GPU more (if needed).

You could also experiment with putting one of the two orphaned 140mm fans in the front-top location (since now you'd be with 3x120mm AIO intakes and a 120mm bottom intake but only a 140mm rear exhaust). This would encourage sucking some of that CPU heat out of the case before it can "contaminate" the rest of the case air.

TL;DR - 360mm rad as front intake, bottom 120mm intake, top 140mm exhaust, rear 140mm exhaust.

 

[Hard_ware]

TL;DR - 360mm rad as front intake, bottom 120mm intake, top 140mm exhaust, rear 140mm exhaust.

If you want to lower CPU temp the top front fan needs to be in intake configuration and top rear fan in outake config.