Noctua NF-F12 PWM

New PWM fans from Noctua

 

In late 2011 Noctua refreshed its entire line of fans by putting out PWM versions. They also introduced a new fan. Let’s look at two of the updated fans and the new one.

 

Here are the NF-P14 PWM and the NF-P12 PWM:

 

 

Noctua engineers took some years to figure out how to make PWM PCB’s so that they operate quietly. Did they succeed? We’ll see.

 

Now let’s look at the new fan, the NF-F12 PWM:

 

 

 

Those vanes are called stators. When a fan’s output is blown through properly designed stators, it focuses its airflow and it increases its static pressure. Noctua says not to expect more airflow from this fan. We shouldn’t see or any better cooling on their coolers. That’s because the NF-F12 PWM is designed to push more air through constricted settings, like radiators.

 

Currently the NF-P12 PWM and the NF-F12 PWM are available retail. The NF-P14 PWM is not. You can’t buy it separately. It only comes with Noctua heatsinks.

 

So let’s look at the P12 PWM and its box:

 

 

 

 

  

 

It has nine blades, and it comes with accessories, of course:

 

 

From the left:

 

A PWM Y-cable. Both branches have gnd, 12v and PWM control lines. Only one has an RPM reporting line, to avoid confusing the motherboard with more than one RPM signal.

 

A 30cm (one foot) extension cable. Since the fan has only a 20cm long (eight inches) cable, this allows a longer reach if you need it.

 

Four “Vibration Compensators.” They come with all Noctua fans. You are supposed to use these to fasten the fan to a case with these. Let me know if you can make these work. I want to know how.

 

There is a packet of four standard fan screws (not shown).

 

In front of the fan is the Low Noise Adapter (L.N.A.), part no. NA-RC6. It will reduce the fan from 1300 rpm to 900 rpm -- and still let the PWM signal control fanspeed.

 

And Noctua provides a product page for the NF-P12.

 

Here is the NF-F12 again:

 

 

The corner cushions are made of silicone rubber to cut down vibrations. The diagram on the inside cover of the box illustrates the advanced technology features of this fan: the stepped inlet design, the inner surface dimples, the improved SSO bearing. It explains that the stators are not evenly spaced around the fan’s circumference. On the next page there is a chart that shows how moving the 11 stators just a little bit to a slightly irregular spacing attenuates some noise spikes. I will predict that we should hear less of a tone from these fans.

 

NF- F12 Product Page.

 

And these are the accessories:

 

 

30cm PWM extension cable.

 

Screws.

 

Low Noise Adaptor. This one is an NA-RC8. It reduces the fan from 1500 rpm to 1200 rpm. I compared the NA-RC8 to the NA-RC6 from the P12. On the D14 the RC8 dropped my P14 to 900 rpm. The RC6 dropped it to 700 rpm. So the NA-RC8 has a stronger resistor than the NA-RC6.

 

The superb Noctua PWM Y-cable. Note that all the cables are beautifully sleeved.

 

Four Vibration-Compensators.

 

Fan Testing:

 

12v: I plugged each fan into my PSU’s 12v Volt line to get the max speed. With the PWM line unplugged you get the maximum rpm a fan will do. You should get 100% fanspeed, but 100% on your motherboard may not reach the fan’s maximum speed.

 

Gnd: Poked a grounded line into each fan’s PWM channel. This emulates 0% PWM duty. In the case of the Noctuas, all three fans stopped. This is unusual PWM fan behavior. Most go to some minimum speed when their PWM rate is zero. And from there the fanspeed will increase with PWM duty; but the increase is often, even usually not linear. We’ll see if the Noctua fans have a linear PWM duty vs. RPM speed curve.

 

The fans then were tested on the Zalman PWM Mate, which is a PWM controller. The PWM Mate generates an approximate 25%, 50%, 75% and 100% PWM duty to each fan. Measured fanspeed with the motherboard utility. Measured the sound pressure level with an SPL meter from 10cm directly in front of the fan. Subtract 20 dB and you have the equivalent sound pressure level of what you would hear one meter away.

 

Here are the results:

 

Noctua fans	PWM duty					Noctua
Fan measurements	0	≈25%	≈50%	≈75%	100%	Rating
NF-F12 PWM RPM	0	363	757	1123	1470	1500
NF-F12 PWM SPL	0	12 dBA	15 dBA	22 dBA	28.5 dBA	22.4 dB
NF-P12 PWM RPM	0	330	686	992	1271	1300
NF-P12 PWM SPL	0	12 dBA	13 dBA	19 dBA	25 dBA	19.8 dB
NF-P14 PWM RPM	0	381	721	991	1225	1200
NF-P14 PWM SPL	0	12 dBA	17 dBA	24 dBA	29.5 dBA	19.6 dB

 

What is not on the chart is the amount of clicking. It’s missing because all the fans had the same amount of clicking at all speeds: none. That’s amazing. Mission One accomplished.

 

Note that the percent PWM duty applied to the fans is approximate. But within the ability to test the RPM and the PWM duty percentage, the speeds of these fans scaled more or less linearly with the PWM duty.

 

As usual for Noctua fans, these were quiet. Even the F12, was quiet and it was spinning at 1470 rpm (some of the SPL results could have been quieter than measured; twelve dBA is the lower limit of the equipment and the environment). Note that discrepancies between what manufacturers measure and what we measure are normal. More important is that the speeds and sound pressure levels for the PWM P12 and P14 are the same as for their non-PWM predecessors.

 

Testing cooling power

 

First, let’s look at the NF-P14 PWM:

 

 

Since the P14 PWM doesn’t have its own box I put it in front of the P12’s box. They are similar fans, after all.

 

Test rig details here.

 

Results:

 

 

The PWM fans cool the same as their corresponding non-PWM fans and with the same noise. The F12 cools the same as the P12, again with the same noise. I did observe that the air normally spilling out the sides of the fin stacks of the D14 (and demonstrate with a tissue) was absent when the F12 was mounted there. It appears that the F12’s airflow truly is focused, as advertised.

 

 

Interim Conclusion

 

The NF-P14 PWM and the NF-P12 PWM perform the same as the non-PWM versions. With the arrival of these PWM fans, the last problem with the NH-P14 has been solved. And the NF-F12 PWM is a fine fan in its own right.

 

But the Noctua “Vibration Compensators” are not very useful.

 

The Noctua isolators fit very tightly on the F12. I was afraid to put one in because I wasn’t sure I could get it out again without breaking it or cutting it off. The worst problem is that they are too short. You have to grip the end with needle nosed pliers to pull one into position. It is hard to get your fingers into the fan’s corner to pull it through.

 

Closeup:

 

 

That picture shows you where the isolator will end up once it is in. You can see that grabbing enough of it to pull it to that position might be quite the task.

 

What you need is a longer one, like this:

 

 

This isolator (http://www.svc.com/sfm-1000.html) is long enough that you can grab it on the other side of the fan from the case. You won’t have to try to get your fingers into some far corner and struggle to get the peg in.

 

But this is not important: when you buy the fan, get aftermarket isolators and leave these in the box.

 

Final thoughts on the Noctua PWM fans:

 

The fans:

 

• They are quiet.
• They do not click.
• They perform well -- identically to their predecessors.
• Their PWM/RPM curves appear to be linear.

 

These fans include excellent accessories:

 

• Their power cables are just the right length.
• If you need a longer cable, one is included.
• They include a PWM Y-cable that is well-designed, and not excessively long.
• All cables are handsomely sleeved.

 

Thanks to Noctua for supplying the PWM fans.

 

 

This is not the first time that I bought these fans, however in an effeort to try and shave some degrees off my load temps, I thought I would give them another go as I was impressed with their performance previously.

Having played around with a few different combinations on my radiator; push vs. pull, using as an exhaust or intake and using different fans (BitFenix Spectres, Corsair SP120s & Gentle Typhoons), I maybe 1 degree difference between the worst & best after 20 mins of LinX....so I was a little dubious that putting the NF-F12s on my radiator would actually improve anything....

....however! My load temperatures are down by ~4 degrees, having repeated the above experiment to allow for any changes in ambient temperatures!

Not only the bonus of the load temps being lower, the fans are a lot quieter than any of the others at max RPM and are barely obtrusive, just adding to the general hum of my PC!

The colors may be enough to put some people off, however I'm lucky that I cannot see them in this build, and for me, the price & colors is a small sacrifice for 4 degree drops in load temperatures!

I did not buy the fans initially for this build as I wanted to compare something else, however I see the error of my ways and will be buying again for my next build!