Does my heatsink need both fans?

[Mach234 (or similar).]

Hey just putting together a new build and noticed the second fan on my heatsink doesn't quite fit (hits the top of the RAM or a metal casing on the mobo that sits proud by the back panel, so I could fit it but it would stand about 3cm high of the heatsink, plus think it looks cooler being able to see the RAM ).

So the question is do you think it really needs the second fan? I've fitted the fan that goes between the two heat stacks and its a really well ventilated case with 3 140mm fans at the front:

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Not going to be doing any overclocking and i'll do some temp checks when I get it up and running, but just wondering what the general concensus was whether a good or bad idea?

Thanks

 

[MissChief]

The only real way to be sure is to try it and check the temperatures. As long as the airflow through the case is good I'd imagine it'll be fine.

 

[doyll]

You will be fine with just 140mm middle fan. NH-D 15 (2x NF-A15) vs NH-D15S (1x NF-A15) is 1-3c difference. Keep in mind that 3c difference would be under unrealistic extreme loads in stress tests for extended periods, which obviously is not how you will be using your PC. Even if your system runs 3c warmer all the time, it's not a significant difference. Idling at 38c instead of 35c and maxing out at 88c instead of 85c won't change performance or system life.

To me the advantage NH-D15S has over NH-D15 (and possibly NH-D15 G2) is NH-D15S offset base moves finpacks 8mm away from PCIe sockets. This means GPUs have 8mm more clearance from cooler. It's much less likely to interfere with graphic cards in nearest PCIe sockets on motherboard that have them very close to CPU socket.

 

[hornetstinger]

The only real way to be sure is to try it and check the temperatures. As long as the airflow through the case is good I'd imagine it'll be fine.

Yeah with the case exhaust fan I can't see reason of CPU fan that's on the left side being much use- you've got movement through the case (intakes) plus the CPU fan on the right.

 

[freddie64]

I used to have a Noctual NH-D14 and ran it with just the middle fan, was absolutely fine.
Will probably be quieter with only one fan as well.

 

[clone]

You will gain very little from having two fans on the cpu cooler, but if they fit then why not.

 

[siumatfung]

You can test the difference but like above it won't make much especially over winter now

 

[Mach234 (or similar).]

Awesome thanks for replies, will run with just the one and do some temp checks when I get it up and running, but as you say with all the other fans hopefully there won't be a noticeable difference

 

[doyll]

Awesome thanks for replies, will run with just the one and do some temp checks when I get it up and running, but as you say with all the other fans hopefully there won't be a noticeable difference

Please let us know how it all comes together.

 

[arknor]

You will gain very little from having two fans on the cpu cooler, but if they fit then why not.

probably gains a lot if the heatsink gets full of dust and you never clean it out with compressed air or a blower.

 

[CaptainRAVE]

Why not, you can run them even slower therefore being quieter.

 

[doyll]

Adding decibels:
dB1+dB2+…+dBn=10log(((10)dB1/10)+((10)dB2/10)+…+((10)dBn/10))

Two identical fans running same speed generating same dB are 3db more noise than single fan at same speed.
Two different fans with on generating 6dB more than other fan generate approximately 1dB more noise than loudest fan.

Two fans in push / pull on single tower or push / push move a little more air. 2 fans move about the same amount of air thru a cooler at same dB as 1 fan running at same dB level. The difference in airflow is small enough it's hard to say which is better. Sometimes the differences are more. It's not because of amount of air going thru cooler, but because of how two vs one changes airflow path thru case.

It all comes down to airflow differences in different builds. And maximum differences are not enough to have a significant effect on cooling or noise levels. We are talking up to maybe a maximum of 2c or 3c. Even at extreme load when peak temps are 75-85c, 2c or 3c really makes no difference.