Question Needs some opinion on cooling with 6 fans.

[AndreiMRC]

Hi guys!

I haven't been building PC for a long time, probably for a good 7 years. Current set-up works just fine with 2 front intake and 1 rear exhaust.

I am planning to get a Lian Li Dynamic Evo case and for aesthetic purpose I bought 6 rbg fans from corsair.

CPU Cooler: Noctua NH-D15 (double fan model)
GPU: ROG Strix 3070
Fans: 6x QL120

Below fan config plan.

1. 3x Side Intake, 1x Rear exhaust, 2x Top exhaust
2. 3x Side Intake, 3x Top exhaust

Considering neutral air pressure from 3 intake and 3 exhaust. (Assuming all fans with the same rpm)
Which configuration will work best?
Should I also reduce exhaust fan rpm to create positive air pressure?

If you have any ideas or suggestions, feel free to discuss. Cheers!

 

[Lafong]

Which configuration will work best?

Best in what respect?

Aesthetic purposes?

The least or most positive or negative pressure?

Temperatures?

Something else? Noise considerations? Dust buildup considerations?

What is best for one purpose is likely not best for the other.

Do you want to use all 6 fans because of their aesthetic effect alone?

 

[AndreiMRC]

Best in what respect?

Aesthetic purposes?

The least or most positive or negative pressure?

Temperatures?

Something else? Noise considerations? Dust buildup considerations?

What is best for one purpose is likely not best for the other.

Do you want to use all 6 fans because of their aesthetic effect alone?

For aesthetic purpose will be planning to 6 fans. To rephrase, best config for lower temps.

Not much issues with noise or dust.

 

[Lafong]

With 6 fans and at least 6 places to put them, you don't have much choice other than to experiment.....particularly when you take into consideration the fan speed controls likely available to you in the BIOS. Lots of variables considering your case, your ambient temps, your fan speed, etc.

You will likely see some variations in temps. It would be up to you to decide if the differences are significant and worth chasing or if they are "good enough" at some point. If a difference of 2 or 3 degrees is important to you, then that might take quite a bit of fiddling.

 

[Paperdoc]

Between the two layouts you suggested, choose the first with 3 x side/front, 2 x top (rear) and 1 x rear. Reason? If you place all 3 exhaust fans in the top, the result in the top front corner is an air flow "short circuit" in which most of the air entering from the top side/front fan is routed almost immediately out of the top front exhaust unit. Do NOT mount a fan in the top front location. Put that 6th fan in the rear location.

 

[AndreiMRC]

Between the two layouts you suggested, choose the first with 3 x side/front, 2 x top (rear) and 1 x rear. Reason? If you place all 3 exhaust fans in the top, the result in the top front corner is an air flow "short circuit" in which most of the air entering from the top side/front fan is routed almost immediately out of the top front exhaust unit. Do NOT mount a fan in the top front location. Put that 6th fan in the rear location.

Ok good to know! Will give that a try...

I might lower the rpm of the 2x top (rear) exhaust fans to create some sort of a positive pressure.
At the same time maintaining 1x rear fan+ 3x intake side fans to having similar rpm, what are your thoughts?

 

[Paperdoc]

Yes, that's a good idea. The match of fan COUNT does not predict positive pressure because the front intake fans have dust filters (I presume) that reduce their air flow slightly. If your top exhaust fans are on the same mobo header this is easy.

What you need is a means of measuring airflow balance. Easiest is a smoke tracer technique. You need a small smoke source - either a cigarette or a smouldering incense stick. Get your system running at idle and move the smoke source close to any cracks or leak points in the case to observe the smoke movement. If it drifts away from the case you have a small positive pressure inside to prevent unfiltered air entry - good. If it drifts into the case, there is a negative pressure. If it moves quite rapidly the pressure difference is too large. You can make some adjustment to slow down the top exhaust fans until the air flow looks right. NEXT, repeat the process with a higher workload. And finally, try again with the max workload you can create. When you have all these cases examined you can decide what is the optimal fan balance setting.