Fan Flow Advice

Housey · 9 Dec 2023 at 11:07

I have ordered my new gaming PC which arrives Sunday from our good friends at OCUK! Already have 4090 and 1200W PSU boxed and ready to add to it and additionally I ordered another 3 x 140mm fans of the spec you see in here.

Question is with AIO at top, GPU fitted directly into the motherboard, 3 x 140mm fans on bottom, 3 x 140mm fans on side and 2 x 120mm fans on rear, what airflow is best for 3 x side and 3 x bottom fans? Assuming pulling in from bottom and pulling out from side, but welcome others views.

I hate cable mess so went silly expensive on the fans (before you all kick me)

VaderDSL · 9 Dec 2023 at 11:31

I’d have bottom and side as intakes and top and rear as exhaust. You might not need the bottom fans, could be worth just testing the different layouts/fan numbers.

Housey · 9 Dec 2023 at 11:52

Thanks, helpful.

The bottom fans were a 2nd thought. I added them to an additional order last night.

VaderDSL · 9 Dec 2023 at 11:55

Only other thing to consider if you don’t use the bottom fans is if you’ll be running negative or positive pressure with the rest of the exhausts vs the side intakes.

But with the radiator restrictions the 3? Side fans should be in taking sufficient airflow to keep it fairly balanced I should think

Housey · 9 Dec 2023 at 11:59

I went 140mm as I believe they are a touch less noisy

Parsley · 9 Dec 2023 at 13:09

I think they're louder if you run them at full, they move more air at the same rpm as a 120mm though, so you can run them quieter overall. 140mm fans have always had a lower pitch to my ears as well, so the noise is less obtrusive.

+1 for Vaders fan flow suggestion as well

. Do try and keep the airflow positive!

Housey · 9 Dec 2023 at 13:20

Parsley said:
Do try and keep the airflow positive!

I will remember each time I turn it on to tell it "you're doing great"

Parsley · 9 Dec 2023 at 13:34

Housey said:
I will remember each time I turn it on to tell it "you're doing great"

And it will reward you for your positivity with less dust

.

Gavster · 9 Dec 2023 at 14:07

+1 For Vader's fan placement

Drumroll · 10 Dec 2023 at 23:35

For every O11 variant, and similar, always has better results as bottom and side intake, top and rear exhaust. AIO on top. Rear lower rpm than top.
Even if the AIO won’t get air as cool as if it was installed on the side as intake, the internal temperature won’t be an issue. Just for those running the infamous Intel and need every last bit of performance to keep their CPU from thermal throttling, I would suggest side intake.
Your GPU is much more temperature sensitive than the CPU. Also, as the AIO is quite a large one, it more than compensates any loss being installed on the top. Internal temperatures will be cooler, RAM, NVME, PCH, MOSFET and specially your GPU will be “happier”.
The only thing that I found that can further improve thermals, at least on the O11D Evo (regular) was to vertical mount the GPU. The 3080 and 3090 needed every last bit of help to run as cool as I like. I don’t think it is as needed with the Evo XL and the 4000 series GPUs.