Optimal PC airflow guide

genetic

Honorary Master
Joined
Apr 26, 2008
Messages
36,832
I recently bought a new PC with the intention of overclocking (no water cooling yet).

The items I bought were;

  • CPU: Intel i7 8700K
  • CPU cooler: Antec C40
  • Mobo: ASUS Maximus X Hero Z370
  • GPU: ASUS Strix Geforce 1060 6GB OC Edition
  • RAM: 32GB G.Skill Trident 3000MHz DDR4 RAM
  • SSD: 500GB Samsung Evo 960
  • PSU: Corsair CX550M 550W
  • Chasis: Phanteks PS400s
After overclocking my CPU to 4.9GHz on all 6 cores at 1.30v, stress testing would result in CPU temps hitting 92c (delidid with Grizzly Liquid Metal).

After following a positive pressure airflow chassis fan guide, and making the rear top mounted fan an exhaust, and the front top mounted fan an intake, my stress temps dropped to 85C under load. That's a 7C drop by just flipping the front top mounted exhaust fan to an intake fan. This obviously aids in drawing in cool air into the CPU fan. Water cooling is the next step, but for a 4.9GHz OC on a air cooled CPU, I'm happy.

I drew this simple fan re-arrangement guide that might help others in optimising their cooling and airflow;

air_flow.jpg
 

Neoprod

Honorary Master
Joined
May 21, 2004
Messages
19,151
^, nice work :)

I didn't enjoy the Phanteks P400 when it came to cooling...the little intakes at the top and bottom are not the best design for cooling. If you're interested, try taking the front cover off and testing your temps again...I was getting 8c-10c lower temps on the GPU and a bit less on the CPU.

The Enthoo Evolv I am using now is better with the front being open at the sides all the way down both sides.
 

bromster

Executive Member
Joined
Nov 2, 2012
Messages
5,286
Rule of thumb is draw air from the bottom and front. Exhausts at the top and back.

It's interesting that you got those results from switching the top fan around. My CM V6 CPU cooler has fans on opposite sides. However as you pictured your case, my CPU cooler draws from bottom and blows out the top to compliment the top/ rear exhaust fan, so perhaps your setup wouldn't help me.


One thing that I know for sure, buying a big, expensive, metal case with 200mm fans is a great investment. I've had my CM HAF X for 5 years and my PC runs at room temperature unless gaming.
 

genetic

Honorary Master
Joined
Apr 26, 2008
Messages
36,832
The Enthoo Evolv I am using now is better with the front being open at the sides all the way down both sides.

Thanks for the info. That's the case I actually wanted, but there was no stock at the time. I also like its aluminium construction and swivel door, which the cheaper P400s doesn't have. :(

Might add it to my wishlist!
 

genetic

Honorary Master
Joined
Apr 26, 2008
Messages
36,832
Rule of thumb is draw air from the bottom and front. Exhausts at the top and back.

The only thing that draws from the bottom of my chassis is the PSU fan, but that is a closed circuit outtake to the rear. My one concern of bottom intakes is dust, but I guess it doesn't really matter where your fans draw their air in from, they will always attract dust particles - no matter how good your dust filtration is.
 
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