3 vs 2 fans on a dual tower CPU cooler...?

[GuruMeditationError]

I was watching Tiny Tom Logan's review of the Noctua NH-D15 on Youtube and he mentioned that adding a third fan to a dual tower CPU cooler makes no difference and that he'd tested this.

Unfortunately I've not been able to find the video where he ran that test or find any kind of test for this at all.

Do people know if it's been tested and where I might be able to find the results?

It seems like it's the one thing that no one's actually looked at. I thought running a search for 3 vs 2 fans on a CPU cooler would have produced at least one or two results but I've found nothing.

[jaslion]

Push pull on a normal tower cooler basically doesn't do more than maybe a 1c decrease. So same goes for a dual tower as it's just 2 towers instead of one. The NHD15 with one fan runs only a tiny bit hotter than it having 2 fans so really doesn't matter.

[GuruMeditationError]

39 minutes ago, jaslion said:

Push pull on a normal tower cooler basically doesn't do more than maybe a 1c decrease. So same goes for a dual tower as it's just 2 towers instead of one. The NHD15 with one fan runs only a tiny bit hotter than it having 2 fans so really doesn't matter.

Thanks for responding, it's most appreciated.

I ran a search and found this: https://www.relaxedtech.com/reviews/noctua/nh-d15s/1#:~:text=It performs great with just,market with their perfect products.

With the NH-D15s, it looks like you get -1C for +1dBA from adding a second NF-A15.

I've always opted for push-pull, based on the idea that the sound waves from identical fans will cancel each other out, for example:
 

Quote

"Overall Results:  Again, as expected the coolers provided nearly identical results with the 2-fan configuration.  What I find rather interesting, is that the sound meter actually read lower with two fans in place vs. a single.  I verified RPMs weren’t different between the two, so I’m a bit dumbfounded." https://www.legitreviews.com/noctua-nh-d15s-versus-nh-d15-cpu-cooler-review_188613/4

The NF-A15 on the NH-D15s it seems is adequate and extremely well balanced with the actual heatsink, so it seems adding a second NF-A15 just isn't necessary, but I'm in a situation where I'm pulling the stock fans in favour of multiple (x3) quiet fans, pushing more air per decibel at 78% the pressure of an NF-A15, per fan. Something I guess isn't that great a concern for most people.

Also, it seems the NH-D15 has beaten out the 8 heat-piped, Akasa Venom Medusa, by 2 degrees C. However the chromax seems to loose 2 degrees to its paint job, so is more or less on par. 

I want the Chromax, but I've already got a Venom Medusa, so...sticking with that.

The question for me at least remains...how much better is 3 fans vs 2, because, if I can get away with 2, I won't have to strip the propriatary heatsinks off of my RAM. 

[jaslion]

5 minutes ago, GuruMeditationError said:

Thanks for responding, it's most appreciated.

I ran a search and found this: https://www.relaxedtech.com/reviews/noctua/nh-d15s/1#:~:text=It performs great with just,market with their perfect products.

With the NH-D15s, it looks like you get -1C for +1dBA from adding an extra NF-A15.

I've always opted for push-pull, based on the idea that the sound waves from identical fans will cancel each other out, for example:
 

The NF-A15 on the NH-D15s it seems is adequate and extremely well balanced with the actual heatsink, so it seems adding a second NF-A15 just isn't necessary, but I'm in a situation where I'm pulling the stock fans in favour of multiple (x3) quiet fans, pushing more air per decibel at 78% the pressure of an NF-A15, per fan. Something I guess isn't that great a concern for most people.

Also, it seems the NH-D15 has beaten out the 8 heat-piped, Akasa Venom Medusa, by 2 degrees C. However the chromax seems to loose 2 degrees to its paint job, so is more or less on par. 

I want the Chromax, but I've already got a Venom Medusa, so...sticking with that.

The question for me at least remains...how much better is 3 fans vs 2, because, if I can get away with 2, I won't have to strip the propriatary heatsinks off of my RAM. 

Wait why are you replacing the noctua fans? They are pretty much the quietest fans on the market?

[GuruMeditationError]

12 minutes ago, jaslion said:

Wait why are you replacing the noctua fans? They are pretty much the quietest fans on the market?

I haven't actually heard the NF-A15, so I don't know what their sound profile/signature is. I'm a bit biased against Noctua because of the motor noise of one of there, iirc, 120mm case fans but that was some years ago now and was only one data point. ...also, there are more efficient fans on the market, just in even worse colours than Noctua's (as I understand it, you can't add dyes to the plastics without altering the performance profile) I've no idea how the NH-D15's actually sound, but I just dismissed (maybe unfairly?) Noctua out of hand many years ago now because of their motor noise / sound profile/signature, and because (if you're willing to put up with, for instance, yellow fan blades) there are more efficient fans out there.   

[jaslion]

14 minutes ago, GuruMeditationError said:

I haven't actually heard the NF-A15, so I don't know what their sound profile/signature is. I'm a bit biased against Noctua because of the motor noise of one of there, iirc, 120mm case fans but that was some years ago now and was only one data point. ...also, there are more efficient fans on the market, just in even worse colours than Noctua's (as I understand it, you can't add dyes to the plastics without altering the performance profile) I've no idea how the NH-D15's actually sound, but I just dismissed (maybe unfairly?) Noctua out of hand many years ago now because of their motor noise / sound profile/signature, and because (if you're willing to put up with, for instance, yellow fan blades) there are more efficient fans out there.   

They are amongst the most silent fans out there (if you are doing dual fans you can even use the low noise adapter and not loose any performance as this is one of the rare cases where 2 fans will help each other a good bit). You can always try them and if you don't like them replace the fan with whatever you wish.

[GuruMeditationError]

12 minutes ago, jaslion said:

They are amongst the most silent fans out there (if you are doing dual fans you can even use the low noise adapter and not loose any performance as this is one of the rare cases where 2 fans will help each other a good bit). You can always try them and if you don't like them replace the fan with whatever you wish.

I'd have to try one, but not really looking at picking one up at the moment due to cost? I'd like an NH-D15 Chromax but it wouldn't be worth the cost for me as I've already got the Venom Medusa. :0/ 

As for the low noise adaptor, that's a good idea but I have my motherboard control fan speeds dynamically, so that they can spin down, hopefully, even further; or spin up to full speed when stuff's under load. It's for a gaming rig and the most stress the CPU sees is at boot and when installing Steam games.  

[jaslion]

47 minutes ago, GuruMeditationError said:

I'd have to try one, but not really looking at picking one up at the moment due to cost? I'd like an NH-D15 Chromax but it wouldn't be worth the cost for me as I've already got the Venom Medusa. :0/ 

As for the low noise adaptor, that's a good idea but I have my motherboard control fan speeds dynamically, so that they can spin down, hopefully, even further; or spin up to full speed when stuff's under load. It's for a gaming rig and the most stress the CPU sees is at boot and when installing Steam games.  

Oh I misunderstood. If you already have a venom medusa then there is little point in getting a nhd15 as they are basically identical in performance. The low noise adapter is basically a limit to max 800rpm thing you can still fully control the speed it just won't go over 800rpm at all. It's more of a legacy thing.

[GuruMeditationError]

3 minutes ago, jaslion said:

Oh I misunderstood. If you already have a venom medusa then there is little point in getting a nhd15 as they are basically identical in performance. The low noise adapter is basically a limit to max 800rpm thing you can still fully control the speed it just won't go over 800rpm at all. It's more of a legacy thing.

Oh okay, thanks, I didn't know it still worked that way. Does that work with voltage control & PWM?

Also, not sure what you mean by legacy?

[jaslion]

Just now, GuruMeditationError said:

Oh okay, thanks, I didn't know it still worked that way. Does that work with voltage control & PWM?

Also, not sure what you mean by legacy?

Yeah still works with both controls. It's more for boards that only have set fan profiles. Think of like 10 years ago where silent mode would still run the fans at like 5v and be audible. Those adapters fixed that issue making it so that you could silence things more on boards with less control.

[GuruMeditationError]

15 minutes ago, jaslion said:

Yeah still works with both controls. It's more for boards that only have set fan profiles. Think of like 10 years ago where silent mode would still run the fans at like 5v and be audible. Those adapters fixed that issue making it so that you could silence things more on boards with less control.

Okay, cool, thanks. Good to know.

Right now I've got to hit the gym.

Re. the original question, I guess mine's a bit of a specific usage case so, maybe I just have to test it myself. :0/

[freeagent]

Before considering adding more fans, or stronger fans to your CPU cooler, look at your case flow first. It is important to move air in a high performance machine. Silence is ok, but if cant be silent all the time, but it can still be quiet.

[GuruMeditationError]

5 hours ago, freeagent said:

Before considering adding more fans, or stronger fans to your CPU cooler, look at your case flow first. It is important to move air in a high performance machine. Silence is ok, but if cant be silent all the time, but it can still be quiet.

Thanks for responding :0)

 

I'm thinking of putting another two of the same fan as is going to be on the heatsink in the base of the case and run them all from the CPU cooler header using a powered PWM fan splitter. That way it should help feed the fans on the CPU cooler.