Pros and cons for various Scythe & Noctua fans?

[fjodor2000]

Hi,

I'm looking for a quiet, high capacity fan with long life span. There seems to be a number to models choose from, and I've narrowed it down to some from Scythe and Noctua. I'm having trouble determining what the pros and cons are of the fans though.

This is the impression I've got from reading a bunch of forum posts and reviews:

* Scythe Slipstream:
+Very quiet
+Available as PWM model too
-Not very long life span (MTBF: 30.000 hours according to Scythe website)
-Low static pressure (which means it's not so good at pushing air through e.g. filters and tight fan grills which cause significant obstruction to airflow)

* Scythe Gentle Typhoon:
+Long life span (MTBF: 100.000 hours according to Scythe website)
+Higher static pressure than Scythe Slipstream
-Not as quiet as the Scythe Slipsteam?
-Some say it has a whining noise, buzzes, and vibrates?

* Scythe S-Flex:
+Very long life span (MTBF: 150.000 hours according to Scythe website)
-Some say it can produce a whining noise?
+/- Not sure how this one differs from the Gentle Typhoon and Slipstream otherwise?

* Noctua NF-S12B:
+Very quiet
+Good airflow to noise ratio (CFM/dbA)
+Very long life span (MTBF: >150.000 hours according to Noctua website)
-Less static pressure than Noctua NF-P12
-Some say it can vibrate if not attached properly?

* Noctua NF-P12:
+Higher static pressure than NF-S12B
-Less quiet than NF-S12B
-Less airflow to noise ratio (CFM/dbA) than NF-S12B (unless placed where high static pressure is needed)
+/-: Otherwise similar to NF-S12B

So, do you think the listed pros and cons above are correct? Or would you like to add/remove/change something?

Please let me know what you think!

[Atragon]

Regarding the noise and performance characteristics of the fans, Martin over on XtremeSystems has been doing a roundup of various 120mm fans when mounted on a radiator. While not directly comparable to open-air tests, it is a fairly comprehensive list that has the fans you're looking at on it. The biggest reason I'm plugging this is that in addition to numerical data, he also recorded each fan while running at various voltages so you can listen to their noise characters yourself.

http://www.xtremesystems.org/forums/sho ... p?t=261778

[Modo]

I have the Noctua S, the S-FLEX, and the SlipStream.

Both have a faint whine at a specific low speed. The S-FLEX does this while still generating turbulence noise, the Noctua below the normally audible speed. This can be annoying if you set the fan to its specific whine speed, or if you make it change speeds often. It can be avoided pretty easy when you know that only some speeds generate the problem. I haven't experienced any vibrations from the Noctua. Maybe someone got a damaged part--shipping will do that sometimes, unfortunately.

[fjodor2000]

@Atragon: Thanks!! That round up at XtremeSystems was truely excellent. And I agree that hearing the fans "live" can be very useful since they often have different noise characteristics.

[fjodor2000]

Both have a faint whine at a specific low speed. The S-FLEX does this while still generating turbulence noise, the Noctua below the normally audible speed.

Just to be sure, do you mean that the whine produced by the S-FLEX is louder, so that it's heard even at higher fan speeds where there is also turbulence noise?

This can be annoying if you set the fan to its specific whine speed, or if you make it change speeds often. It can be avoided pretty easy when you know that only some speeds generate the problem.

The Noctua NF-S12B comes with adapters that set the fan speed to fixed speeds (600, 900 or 1200 rpm). Does it whine at any of these fixed speeds? If so, have you been able to fine tune it with an external voltage regulator?

Finally, do you know how the Scythe S-FLEX differs from the Scythe Slipstream and Gentle Typhoon? I know the S-FLEX has the longest life span in MTBF, but apart from than?

[Modo]

Just to be sure, do you mean that the whine produced by the S-FLEX is louder, so that it's heard even at higher fan speeds where there is also turbulence noise?

No, it's not louder. The whine when using the S-FLEX happens at a higher (but very specific) speed than with the Noctua, so it's actually partially drowned out by turbulence noise.

The Noctua NF-S12B comes with adapters that set the fan speed to fixed speeds (600, 900 or 1200 rpm). Does it whine at any of these fixed speeds? If so, have you been able to fine tune it with an external voltage regulator?

It happens below 600 rpm, at a speed where no air noise is present anymore. The Noctua kept hitting this speed when my PC was idle, and I wanted the fans to be inaudible, so I gave it away. There shouldn't be a problem when using the included adapters or some other control mechanism. (YMMV, of course.)

Finally, do you know how the Scythe S-FLEX differs from the Scythe Slipstream and Gentle Typhoon? I know the S-FLEX has the longest life span in MTBF, but apart from than?

I think the bearing is the feature of the S-FLEX. In addition to a long lifespan, you get complete silence when you slow the fan down to about 550 rpm, depending on your hearing. You can put one in your PC, set up some automatic speed control, and not think about fans even again (until you replace the rig, that is ). Note that there are now other fans with bearings of similar and even better quality.

[fjodor2000]

Note that there are now other fans with bearings of similar and even better quality.

Any particular ones you could mention? Are they also better than the S-FLEX when it comes to low noise and CFM?

[Modo]

The Noiseblocker BlackSilent Pro looks really good (180 khours MTBF; very positive user testimonies). There are Thermalright fans that look exactly like the S-FLEX, just with a different badge. Enermax has the TB Silence series, with a bonus--a special system for easy dismantling (to wash the blades). There are even cheap Arctic Cooling fans with fluid dynamic bearings (same type as the S-FLEX, don't know about reliability). Just to name a few.

The noise/CFM thing is, to my mind, a moot point by now. Good 120 mm fans have very comparable noise characteristics. You get one with fewer blades for a heatsink, or with more blades for the case. Heck, get the right color if you feel like it. As long as you stick to the FDB-type bearings (they have different names), you can set the noise level as low as you like, and as low as your rig can take. If you really need lots of airflow with low noise, look for 140 mm fans--they are the next evolutionary step.