[SOLVED] Airflow help

[Auchhior]

Hello, so currently I have the airflow set up as below. With three intake fans and two exhaust fans, the case is a Cougar MX330-G. In the PC I have a i7-9700K on a Asus Prime Z390-P and a Gigabyte 1080 Windforce(Here's the full list if it's needed: https://pcpartpicker.com/user/Auchhior/saved/R4n6D3). I read that having top as in take is a bad idea, but I also was worried about only having two intake fans vs three exhaust fans and that leading to negative air pressure inside the case. The fans in the front two slots and the top two slots are Rosewill ROCF-13001s and the back exhaust is the fan that came with the case.

Thanks!

 

[NightHawkRMX]

Negative pressure isn't really a bad thing aside from more dust.

Top fans should always be exhaust, otherwise you are fighting the fact hot air naturally rises

 

[Phaaze88]

Top intake is not effective here; you don't have the right hardware for it.
Best thing is to either:
A)Leave the front and rear fan as they are.
Flip the top intake fan to exhaust.
This will prioritize gpu thermals.

B)Remove both top fans and leave the rest as is.
This prioritizes cpu thermals - the air cooler's fan draws air from the front as well as the top. But when you put fans up there, you disrupt that.

 

[iPeekYou]

You don't want fans with opposing directions next to each other. The effect fans have on airflow is strongest to devices near them; i.e. if you have two fans side-by-side in opposite directions, much of the air drawn in is sucked out through the other.

Your top rear exhaust fan is good, top front as intake not so much. a) top front intake directly disrupts the front to back airflow from the nearest front fan, and b) my point above. Bit-tech's experiment on this. I played around with fan configs myself a few months ago, and found that top fans don't do much good, except that top rear as exhaust nets me 2-3 deg C cooler on VRM and 1C on CPU (with a typical 120mm single tower cooler).

Other results:Top intake at the rear adds 7C to VRM temps, both top front as intake or exhaust adds 2-3C. All fans are the same exact model to remove as much variable as I can.

IMO, the support for 2x120mm or 140mm up top is mainly for mounting 240mm or 280mm AIO there. Otherwise, top rear as exhaust, leave the top front open or as exhaust. Mind that you might suck in more dust through the gaps on the case if both top fans are used for exhaust.

Top fans as intake is need-to-use basis only, for enclosures with very poor airflow from the front (see: Bitfenix Enso), and prioritizes CPU cooling over GPU cooling in that case. It's a band-aid for an open wound.

No need to worry so much about how many fans you have installed in your system, most PCs only need decent airflow from the front (mesh panel, or solid panel with decent vents from the side), and a good rear exhaust fan. Yours have mesh front, I'd argue you can even run slower fans up front and see no difference in temps.

 

[Auchhior]

Thanks for all your help! I figure I'll just take out the top intake fan instead of swapping its direction.

 

[iPeekYou]

Thanks for all your help! I figure I'll just take out the top intake fan instead of swapping its direction.

Glad to help. 2x intake fans at the front with mesh panel, and 1 rear is all you need. Top rear exhaust can't hurt, not necessarily adding cooling either.