NF-A12x25 PWM Fans on an NH-D14/15

[drakulton]

Hi
Would there be any appreciable difference if the stock fans were removed from a Noctua NH-D14 or D15 and replaced with 2 or 3 NF-A12x25 PWM Fans?

Just curious as their latest top of the range cooler is smaller but has the NF-A12x25 PWM Fans.

Ta muchly.

 

[Meddling-Monk]

Depends on what difference you're looking for.

If in terms of performance only, then all fans at max, then the newer A12x25 can certainly keep up with the slightly larger fans, but will likely lose out in terms of air being pushed around at full revs when there's no obstruction.
But if you factor in the other factors, such as higher static pressure on the A12x25 compared to the other fans (for rads and other densely packed obstacles), as well as amount of air pushed at lower revs of the fan comparatively, thereby producing far less noise, and the A12x25 starts to look (well, "sound") a lot better than the existing larger fans on the D14 and D15.

Noctua are apparently working on the newer A14x25 and A15x25, so those will likely be superior to the A12x25 in larger form, but we have no idea when those are coming yet.

 

[doyll]

NH-D14 and NH-D15 are designed for 140mm fans. So while NH-A12x25 will likely move as much or more air it will do so in a smaller flow pattern in cooler designed for 140mm fan flow pattern, so at a guess there will likely be little or no change. Change may be a little lower temps, or maybe a little higher temps .. but even if a little lower, so little (1-2c) it's not worth the expense.

 

[Meddling-Monk]

If expense isn't an issue though, there is one advantage the A12x25 has over the A14 and A15 models with the D14 and D15, and that's at maximum RPM, the noise is much less pronounced and less in volume, and so much easier on the ears if you ever run the fans at max speeds.

 

[doyll]

I don't think the A12x25 are worth paying more for when used on coolers. These coolers have very low airflow resistance so the higher pressure rating is moot point, and A12x25 has significantly less airflow at similar noise level in free airflow .. lower 140mm fan speed a little to give same noise level and still have much better airflow over wider area.

NH-A12x25 @ 2000rpm deliver 102.1m³/h & 22.6dB(A) no resistance
NF-A14 @ 1500rpm deliver 140.2m³/h & 24.6dB(A) no resistance
NF-A15 @ 1500rpm deliver 140.2m³/h and 24.5dB(A) no resistance

 

[Meddling-Monk]

Having both fans (A12x25 and A14) and the U12A (D12) Cooler, I would agree that adding extra expense needed to grab a new set of fans isn't great. Great if it's free upgrade or free samples etc (dunno how you get those, would love to have a few more fans to play around with personally ), but not as an extra purchase expense.

From personal testing, I can tell you that the A14 at ~60% speeds is where the noise is imperceivably different from lower speeds. Once you hit anything above 60% or thereabouts, you'll notice the A14 cranking up. The A12x25 however, is only noticed once you reach at least 75-80% before you notice its cranked things up, or if the fan noise becomes annoying (not just air/wind rush noise). Used LNA in both fans. Whilst the numbers are not direct, but a rough percentage down would have both the A12x25 and the A14 giving roughly the same numbers for airflow and noise levels (but at different speeds); 76-81m2/h on A12x25 vs 84 on the A14/A15. The A12x25 at max speeds (with LNA) doesn't sound nearly as bad as the A14 at around 80% of its rated speed, so again, there's a certain amount of noise difference between the two, not a lot though, but it's there, favouring the A12x25 over the A14/A15.

So in short, the A12x25 is really comparable to the A14 or A15, but smaller and when running +20% more compared to the bigger A14/A15 speed (to retain same airflow and noise produced). The A12x25 only loses out entirely at the top end max airflow, but if you really are needing that type of airflow for cooling, you'd probably be after other stuff instead.

The A12x25 is better if your gear is 120mm based, like the U12A cooler. As fitting a larger fan won't really work as well. Hence why Noctua likely paired the A12x25 with the U12A. But for more larger devices, the A12x25 will work just as well as the default A14 or A15 that's supplied (as the D14 or D15) and can be moved to other devices as well as not be as hampered if airflow is heavily restricted. But when cost (or getting new A12x25's) is involved, it won't look so great. Again, nothing really new what doyll and I have already posted, just posting up however that the noise produced by the A12x25 is better (less noticable) compared to the A14, and that can be a major factor for some.

 

[drakulton]

@Meddling-Monk @doyll

Gents,

Thanks for the info, I was just curious as some of the reviews were stating that the smaller coolers like the U12A were as good as the NH-D15/15 and it was mostly down to the fans.
I've got a couple of PWM NH-D14 so the cost of fans would be prohibitive.

 

[doyll]

I don't know of any 120mm fanned coolers that cool as well as 140mm fanned coolers. They are typically 3-7 higher temped at full load tan top tier 140mm fanned coolers .. and usually making more noise trying to keep up.

Take a look at Thermalright Le Grand Macho RT which is arguably the very best cooler out there right now. It is 147x152x159mm (LxWxH) with 147x152x112mm of that in fins and has 7x 6mm heatpipes.

That said, arguably the best performance to price is TRUE Spirit 140 Power for arround 50 quid measuring 155x53.4x171.2mm (LxWxH) with 155x53x110mm in fins, but it has 6x 8mm heatpipes .. 8mm heatpipes have much more surface area and volume. The cross-sectional surface area nd volume of 6mm heatpipes is 18.8mm & 28.26sq mm .. while 8mm heatpipes have 25.12mm & volume of 50.24sq mm . .. that's a huge difference in heatpipe heated vapor flow area and liquid returning to heast source wicking surface area.

8mm heatpipes have 25.12mm surface area & 50.24sq mm volume per mm of heatpipe.
6mm heatpipes have 18.8mm surface area & 28.26sq mm volume per mm of heatpipe.
That is a differeence 6.32mm more surface & 21.98sq mm more volume for 8mm heatpipes over 6mm heatpipes.

 

[Meddling-Monk]

Well, the U12A has the one advantage no other cooler really has that also performs in the same league (performance wise): Size. Technically, as it's using the A12x25, you could get away with powering a fairly high end CPU using just a single fan, and then have access to all RAM slots (if you're using a 6/8 DIMM slot motherboard) and if you're using RAM that has high heat spreaders (although, other than RGB, which will get covered by the fan, why would you anyway? ). In short, if you're using normal RAM, the U12A can fit in there without excess space required (with both fans) and still cool like a D14/D15 setup. Something not a lot of other coolers can really claim they can do easily.

 

[drakulton]

I got a good deal on some ddr3, but the ram heatsink was almost taller than the NH-D14. Two minutes later, the heatinks were removed and the memory sits nicely under the CPU cooler. The noctua fans look a lot better under purple LED light too!

 

[Meddling-Monk]

Never bothered with RGB lighting inside the case myself despite having a windowed case. But a quick search around on the Noctua's in purple lighting do seem to have a nice look to them, probably caused from the colour of the noctua beige and brown to reflect certain wavelengths more and causing a nicer look to it. Might do that at some point if I can find some nice silent RGB fans (for ultra silent exhaust) at the top of the case.

 

[drakulton]

Never bothered with RGB lighting inside the case myself despite having a windowed case. But a quick search around on the Noctua's in purple lighting do seem to have a nice look to them, probably caused from the colour of the noctua beige and brown to reflect certain wavelengths more and causing a nicer look to it. Might do that at some point if I can find some nice silent RGB fans (for ultra silent exhaust) at the top of the case.

Purple Noctua-ness

 

[Meddling-Monk]

I like!

But then, I'm a graphics/image person, so colours always a selling point for me if it works.

Just found out something: My A14 when put at 50% via PWM and using a LNA has the dreaded ticking sound that plagues the Silent Wing 3s (a tick sound that happens every second or so, looking at the fan I can also see it slow down momentarily when it happens). It doesn't happen when I push it to 60% with LNA on. Will be contacting Noctua over if this is normal and likely get a RMA for it.

 

[drakulton]

I like!

But then, I'm a graphics/image person, so colours always a selling point for me if it works.

Just found out something: My A14 when put at 50% via PWM and using a LNA has the dreaded ticking sound that plagues the Silent Wing 3s (a tick sound that happens every second or so, looking at the fan I can also see it slow down momentarily when it happens). It doesn't happen when I push it to 60% with LNA on. Will be contacting Noctua over if this is normal and likely get a RMA for it.

Sadly it seems that you're not the only one with a ticking fan. There are quite a few reports of it happening.

 

[doyll]

I like!

But then, I'm a graphics/image person, so colours always a selling point for me if it works.

Just found out something: My A14 when put at 50% via PWM and using a LNA has the dreaded ticking sound that plagues the Silent Wing 3s (a tick sound that happens every second or so, looking at the fan I can also see it slow down momentarily when it happens). It doesn't happen when I push it to 60% with LNA on. Will be contacting Noctua over if this is normal and likely get a RMA for it.

Can you just not use the LNA?

 

[Meddling-Monk]

Can you just not use the LNA?

Could do. It's basically the same number roughly.

But then I would have purchased a different fan then that didn't cost as much when I needed to run it under the 50% margin and expected clicking/ticking noises as well (in fact I have an older fan that could have taken that place entirely). So its really a check in with them if this is expected or not (I don't think it is from the numerous RMA I've been reading) and seeing what options are available.

The A12x25 is fine with all speeds from my testing, but the A14 starts the ticking with LNA at 50% or below (previously was running it at 60% minimum, but managed to get it hooked to a fan header that can go lower now). Incidentally, this A14 also had a bad humming sound at ~65%+, so it's sounding like there was an issue with it originally and this low speed ticking just confirmed it. I could keep it and only run it at 50% (60% with LNA) but again, ~£19 for only one setting on the fan? Kinda defeats the purpose of the PWM option. As well as sink my money for something I wouldn't need (since an older and more clicking fan could have taken its place).