Comparing stock fan vs. Noctua in an SE/30 with temperature data

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polpo

Tinkerer
Oct 30, 2021
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Steve Jobs and I don't have much in common, but one thing that could be said about the both of us is our hatred of fan noise. One of the very first things I do to quiet down an SE or SE/30 is replace the stock fan with a Noctua NF-A6x25 FLX. But I and others have wondered - just how well does the Noctua perform? JDW has a video comparing the stock fans vs. a Noctua but it's missing one crucial bit of information: how well do the different fans actually cool the system? Specifically, how well do they cool the flyback transformer? I'm most concerned about the flyback since it's probably the most irreplaceable part of the system's analog board, since there are no common drop-in replacements that I am aware of. So I decided to get some hard data so I can feel comfortable that the quieter Noctua fan is doing a good job compared to the stock fans.

The test setup:

- Macintosh SE/30, pretty much stock except with an Asante MacCon Ethernet card and no internal hard drive. The analog board was recapped a couple years ago.
- I measured the temperature of the flyback with a Fluke 87 V DMM with a Fluke Type T thermocouple temperature probe, stuck to the flyback with Kapton tape and a dab of thermal paste to ensure good thermal conductivity. I routed the wire for the thermal probe through the security lock hole in the back of the case.
- The tests happened in my semi-heated basement, with ambient temperatures around 63-66 degrees F.
- I did two tests each day, the first one first thing in the morning, and the second in the early afternoon after having a desk fan pointed at the open computer for a couple hours to get the temps of everything back to ambient.
- I'd power the system up and let it sit at the disk with blinking question mark for 90 minutes, logging the temperature at start, 15 minutes, 30 minutes, 60 minutes, and 90 minutes.

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The fans in question:

- Canon CF60-T119N1D. This was the original fan that came in this SE/30, and I also have an SE that came with this model.
- Sanyo Denki DC Pico Ace 109P0612M402. This fan came in another SE/30 that I have.
- Noctua NF-A6x25 FLX. This is the "3 wire" version of the fan that doesn't have PWM control. It's run at the full 12V and not through the "low noise adapter" that comes with the fan.

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The data:

I tested over the course of 2 days. In the morning of the 2nd day when I opened the case the temperature probe pulled out of the kapton tape, so I reapplied new tape and thermal paste. I tested the Noctua on both days to see how consistent the temperatures were with the new tape and paste.

Day 1 testing:
Noctua NF-A6x25 FLXCanon CF60-T119N1D
0 min64.3°F67.0°F
15 min93.7°F99.8°F
30 min105.1°F112.5°F
60 min111.0°F121.5°F
90 min114.0°F124.4°F

Day 2 testing:
Sanyo Denki 109P0612M402Noctua NF-A6x25 FLX
0 min64.2°F66.2°F
15 min104.1°F95.2°F
30 min119.9°F107.9°F
60 min129.7°F110.4°F
90 min132.4°F112.3°F

Conclusions:

The Noctua is not only much quieter than the two stock fans I have, it cools better, too. This isn't too surprising to me: due to the size of the motor on the stock fans, they have fairly small blades, especially the Sanyo Denki one. The Noctua has a much larger blade area. Most of the noise from the stock fans comes from the motor and in my opinion they are much more annoying sounding than the Noctua.
 
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Nycturne

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Dec 18, 2024
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I'm curious about the CFM ratings just to see how much of this is spec vs age, if possible.

With the Quadra 605 I received, the Noctua was slightly better in terms of rated CFM, and your data seems to suggest that the CFM of the OEM fans here are similar to the CFM of the OEM fan for the LCIII/475.
 

polpo

Tinkerer
Oct 30, 2021
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I'm curious about the CFM ratings just to see how much of this is spec vs age, if possible.

With the Quadra 605 I received, the Noctua was slightly better in terms of rated CFM, and your data seems to suggest that the CFM of the OEM fans here are similar to the CFM of the OEM fan for the LCIII/475.
It's a bit hard to find exact data for the stock fans, but another stock fan for the SE chassis is the Elina HDF6025L-12MB and it's still listed in a recent datasheet with the specs of 0.36m3/min which is 12.7 CFM, and a static pressure of 21.6 Pa. As for the Sanyo Denki fan, I found an old Jameco catalog on the Internet Archive that lists the Sanyo Denki at 14 CFM and another elctronics catalog that lists it at 10 CFM, and a close part number in a more recent Sanyo Denki catalog that lists it at 12.6 CFM and a static pressure of 19.6 Pa. To compare, the Noctua lists (with some conversion) 13.83 CFM and static pressure of 21.4 Pa.
 
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scj312

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Oct 29, 2021
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This is very useful data! I'd also be very curious how the SE's original "squirrel-cage" fan performs in comparison to these axial fans (thermally--we already know the noise situation is not good!)
 

JDW

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The CFM spec speaks about "air flow" and that tends to be tied to the RPM spec. Here's how the 5 fans I tested show airflow in the back, which admitedly is also impacted by the blade design. The blades and fan shape can determine whether more air flows straight out the back (which push my white papers out more) or whether some air shoots out the sides.

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What I found most interesting when comparing the above air flow pic to @polpo 's data is the fact that his data shows the Sanyo "PicoAce" fan to offer the least cooling of the 3 fans he tested (one of which being the Noctua I used). But you can see from the above that the Pico Ace shoots a bit more air straight out the back (note the angle of the white papers). But by and large, as you ramp up the fan RPM, the more air flows straight out the back, as shown by the angle of the papers in the pic above.
 

Nycturne

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Dec 18, 2024
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The CFM spec speaks about "air flow" and that tends to be tied to the RPM spec. Here's how the 5 fans I tested show airflow in the back, which admitedly is also impacted by the blade design. The blades and fan shape can determine whether more air flows straight out the back (which push my white papers out more) or whether some air shoots out the sides.

Correct me if I'm wrong here, but this test looks to be more affected by static pressure than airflow?

You're creating resistance that the airflow has to overcome (the paper blocking the outlet), which is important if you are pushing air through tight spaces like a modern radiator in a liquid cooled setup. However, if the goal is to just move air around, and you aren't obstructing the airflow, then it's possible to build a fan that moves more air, but it might not be able to match a different fan design in terms of the air pressure produced. It's not always straight-forward which fan will perform best without knowing the specifics of where it is mounted and the type of obstructions it has, if any. How a fan grill is cut in the plastic matters as well, as it might help present less of an obstacle to an airflow optimized fan depending on the design.

I think the interesting bit is that the spec sheets put the Sanyo Denki at the bottom for both CFM and static pressure, but you are showing higher static pressure.
 

JDW

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Well, in terms of what I said in my previous post about the possibility of some air shooting out the sides instead of all the air going straight out back, I suppose "static pressure" is indeed at work too. But regardless of "static pressure," if you look at my photo, the angle at which those papers are being pushed back is largely tied to the fan's RPM spec. Note how much more the 3900rpm SanAce fan blows those papers out of its way (and blows your eardrums away too, let me tell you).

But at the end of the day, what matters is INTERNAL COOLING, and @polpo has show us the actual internal temperatures, which are meaningful. It's also very encouraging too because Noctua is a very quiet fan, yet it cools better than the louder fans.

BOTTOM LINE: Get one of the two Noctua fan models for your SE or SE/30:

• Noctua 60x25mm PWM 12V: lower current consumption than FLX
• Noctua 60x25mm FLX 12V: includes pass-thru connector for HDD 4-pin power plug

Here's the email conversation I had with Noctua about the two fan models...

2019/08/20 5:09 PM, "James Wages":

Thank you for the information. In that case, I will get the PWM version since it has lower current consumption.

I appreciate your kind help!

Sincerely,

James Wages



2019/08/20 5:06 PM, "Noctua Support" <[email protected]>:

Greetings from Noctua!

Both motors are absolutely inaudible.

Kind regards,

Emanuel Fankhauser

Your Noctua Support-Team



On Mon, 19 Aug at 11:24 PM, James Wages wrote:

In that case, which motor of the two is quieter when operated at 3000rpm?

(My intention is to run the fan at full speed using only 2 wires.)


Thank you,

James Wages



On Aug 19, 2019, at 7:31 PM, Noctua Support <[email protected]> wrote:

Greetings from Noctua!

Thank you very much for contacting us.

Because those fans have a different motor inside. :)

Kind regards,

Your Noctua Support-Team



On Aug 18, 2019 at 5:19 AM, James Wages wrote:

Hello,

Why does your 60x25mm 3-wire FLX version fan require 120mA max when your 60x25mm 4-wire PWM version requires only 80mA max, seeing both fans are 3000rpm?

Thank you,

James Wages
 

Fizzbinn

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Nov 29, 2021
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I bought these from OWC a few years ago, but cannot find a current seller. It seems I was lucky.

View attachment 20443

So boringly pretty! why can't these be their standard offering!?

Noctua: Our case fans are tan and brown because that's the color of PC's these days, right?
Noctua: Our case fans are tan and brown because we think it's an ironic branding choice in the face of trendy clear plastic and RGB lighting options!
Noctua: Our case fans are tan and brown because who cares, you can't see them inside the case!
 

JDW

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So boringly pretty! why can't these be their standard offering!?
My biggest issue with Noctua isn't the color, although I agree that tan isn't a very brilliant color choice. That's because it's not that easy to spot the tan color inside an SE/30 unless you are constantly gawking at it from the back. No, my biggest issue is PRICE, in large part because they include all those TOTALLY UNNECESSARY cables. Just sell the fan and also sell the cables as an option! They'd make more money selling cables as options, and there would be no waste that way either. Because right now, in their earnest to reduce the number of SKU's they sell, they are selling a bunch of adapters that many people won't need, and when you sell a lot of fans to the same people, those unneeded cables really add up. It's expensive and wasteful!

Here in Japan, the FLX 60mm sells for ¥3100 on Amazon, which is about $21 USD:

 

Oelmuvun

New Tinkerer
Oct 23, 2024
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I thought they had the Redux line which were just the fan in a box at a reduced price? And if I recall they are light and dark grey plastic even.