Question How many fans is too many fans?

[tibbakoi]

I've replaced the stock DC fans in my Corsair Carbide 100R silent edition case with Noctua NF-S12B PWM front and back, and am wondering about the benefits of adding a second fan to the front. The intake fan is currently half way up, above the drive bays, and I could add one of the old stock fans as a second intake lower down at the level of the drive bays. My mobo only has 2 system fan headers, but the case comes with a 3-speed DC fan controller (which I'd not used in my previous build as I didn't like the idea of the fan speed controller without a temperature sensor).

Is there any benefit to adding a second front fan that isn't connected to the rest of the system sensors? Or would it be negilible? Would it disrupt the airflow? Would the exhaust fan need to be adjusted to account for more intake fans?

 

[USAFRet]

This is "too many"
https://www.engadget.com/2007-11-25-66-fan-case-mod-exemplifies-overkill.html

How many do you need?
Well, how are your system temps, under load?

 

[tibbakoi]

This is "too many"
https://www.engadget.com/2007-11-25-66-fan-case-mod-exemplifies-overkill.html

How many do you need?
Well, how are your system temps, under load?

That is definitely too many!

Idle temps are 40-50, but that's with a probably compounding issue (see my other post) - I'm wondering if using the spare fan would be helpful

 

[USAFRet]

That is definitely too many!

Idle temps are 40-50, but that's with a probably compounding issue (see my other post) - I'm wondering if using the spare fan would be helpful

Idle temp does not count.
Under load is what is needed.

If the fan isn't mounted correctly, fix that.

And more fans on the case don't really affect CPU temps.

 

[Rokinamerica]

I run my Thermaltake v-150 with 2 intake fans in front, both at top and middle positions, 1 exhaust on top and 1 exhaust in back. Currently with 3 27' screens streaming a movie, CPU (10600) is 31C and GPU (12GB 2060) is 35C. Ambient temp in my office is 63F (office is in my garage) with door open.

 

[JohnBonhamsGhost]

How many fans is too many fans?

the amount of fans and the speeds that they run at depends on what level of fan noise you want to hear and what temperatures you'd like to see.

the more cool air brought in, along with the amount of warmed air pumped out, determines a lot of your system-wide temperatures.

the cooler the air your CPU cooler is blowing through it's fins the lower the temperatures will be but if you're not exhausting the warmed air at a similar pace then it can build up and continue to warm other components while the CPU cooler may start to recycle that warmed air and itself get warmer & warmer.

you can see an image of my system-wide cooling setup in my signature.
with this type of arrangement i am able to keep CPU, GPU, VRM, RAM, everything usually idling in the lower 30s°C and under max loads ~55-65°C.
this is considering that in spring through summer the indoor environment stays ~26°C / 78°F.
during deep winter months my system temps usually stay ~4-5°C cooler on average.
plus using the higher quality fan models that i have i can keep the system relatively silent.

 

[hotaru.hino]

There's certainly a point of diminishing returns but there's no definitive formula for that. As mentioned it depends on your tolerance to fan noise and/or how comfortable you are with the thermals of the system.

Though as a rule of thumb, I would argue the "too much" point objectively speaking is when the fans start interfering with each other. For instance, if your case provides fan mounts across the front and top, adding a fan in the topmost position in the front and the frontmost position in the top I can't see as doing anything better than if you had just one or the other, regardless of how the fans are pointed.