S-Flex SFF21D 120mm "8.7dB" mini review

[ckolivas]

Ok here's a summary of the manufacturer's data.

Scythe S-FLEX 120mm Fan SFF21D

Features for Scythe S-FLEXâ„¢ 12cm Case Fan

Equipped with Genuine S-FDB* Bearing

This fan is equipped with genuine S-FDB (SONY Fluid Dynamic Bearing) made by SONY corporation.

Market Leading Low-Noise Level

S-FDB technology drastically eliminates the friction between the bearing and the shaft which makes this fan nearly inaudible to human ears. Additional suction magnet optimizes the magnetic force balance within the rotor to achieve the absolute silence. To further achieve the absolute silence, the fan is equipped with the Linear drive IC for reducing electromagnetic noise.

Outstanding Long Life of 150000 Hours

Patent Pending "S-FDB" structure allows the fan to last up to 150000 hours.

Anti-Shock Ability

Conventional ball bearing carries a point contacting structure for the rotation, which gives point supporting situations at dropping impact to damage ball bearing surface which could cause irregular noises. The S-FDB carries a surface contact mechanism for improved anti-shock structure, which is 5 times stronger than the conventional ball bearing.

Scythe S-FLEX 120mm Fan SFF21D

Features for Scythe S-FLEXâ„¢ 12cm Case Fan

Equipped with Genuine S-FDB* Bearing

This fan is equipped with genuine S-FDB (SONY Fluid Dynamic Bearing) made by SONY corporation.

Market Leading Low-Noise Level

S-FDB technology drastically eliminates the friction between the bearing and the shaft which makes this fan nearly inaudible to human ears. Additional suction magnet optimizes the magnetic force balance within the rotor to achieve the absolute silence. To further achieve the absolute silence, the fan is equipped with the Linear drive IC for reducing electromagnetic noise.

Outstanding Long Life of 150000 Hours

Patent Pending "S-FDB" structure allows the fan to last up to 150000 hours.

Anti-Shock Ability

Conventional ball bearing carries a point contacting structure for the rotation, which gives point supporting situations at dropping impact to damage ball bearing surface which could cause irregular noises. The S-FDB carries a surface contact mechanism for improved anti-shock structure, which is 5 times stronger than the conventional ball bearing.

Specifications for Scythe S-FLEXâ„¢ 12cm Case Fan

Model Number: S-FLEX SFF21D (800rpm)

Dimensions: 120 x 120 x 25mm

Specifications: 800rpm Version: 33.5CFM / 8.7dBA / DC12V / 0.10A

Connector: 3-pin (4-pin adaptor included)

Cable Length: 30cm

Bearing Type: S-FDB (Fluid Dynamic Bearing by SONY Corporation)

MTBF: 150 000 hours

S-FLEXâ„¢ is a registered trademark of SONY Corporation

There have been some interesting reviews on the 80mm fans, and some on the higher speed "E" 120mm fans, and other websites have shown some good figures on these D fans so I thought I'd buy a few and try them. I purchased 4 from pccasegear.com in Australia. They were excellent in delivering them less than 24 hours from my order to my door.

They come packaged in a stiff plastic shell with an outer plastic wrapper.
(most photos have enlargements just click on them)




The detail on the top of the package says the fan appears to be basically made by Sony.




Lots of advertising bullsh... jargon on the back.




The contents are pretty standard 3 pin based, with a 4 pin adapter that nicely includes an rpm monitor you can plug in




The fan has all important partially open corners and looks like so close up:




Finally they mount without a hitch on the Thermalright ultra 120 (one of the uses I had in mind for them)



Ok so on to the review.

On visual inspection there are no outstanding features of this 7 blade fan and it has zero bling value which to me is a good thing. It is about average weight for a fan of this size (unlike say the Aerocool fans which are much lighter).

I'm fortunate in that I live in an extremely quiet area and the downstairs of my house at night is nigh on silent where a Nexus 120mm fan at 12V is downright noisy.

So I plugged it in and fired it up via various means. Many of my colleagues have criticised me at work for giving the bad news last which always downplays things so I'll reverse my usual stance, and do the ugly, the bad and then the good.

Bear in mind that this fan runs at 800rpm at maximum voltage...

This fan buzzes like a blowfly in heat with pwm control so that as an option to undervolt it is basically out.

8.7dB? Not in your wildest dreams. I certainly didn't believe it on the ad alone, and in the flesh I could tell it definitely was not 8.7dB.

Most fans are known to start at 7V. This one? Nope.

So it doesn't really start at low voltage. However it did go down in voltage once started, but I was not really happy that the way it ran at 7V would be reliable. A zalman fan mate was a decent match for it, but could easily drop it to a speed below which it refused to turn.

Ok that's the ugly and the bad out of the way. Now onto the good.

Vibration in the hand test? Very little, and almost nothing transmitted to the heat sink when it was mounted even without the rubber stoppers included in the ultra 120. Actually at equivalent voltage/speed the Nexus felt slightly smoother, but it didn't seem to make an audible difference.

This is one damn quiet fan at full voltage. At 12V I compared its noise signature and apparent loudness to a Nexus 120mm at 7V. They are very similar in loudness, with a higher pitched sound from the s-flex. Neither fans' sound characteristic was unpleasant. Furthermore it didn't make a difference what direction I held the fan at which may be nice for unusual position mountings of PSUs and heatsinks. The s-flex was only really audible in the presence of other components when I got up close to it (less than a foot). Mounted on the heatsink it almost seemed quieter (but that could have been my imagination), however it definitely was not noisier. Once mounted in the box I could not discern the sound of the fan over any other components, the WD5000KS suspended in an Antec Solo being the loudest.

Well the main attraction for me to this fan was that it was going to be probably the right compromise in terms of flow and noise at default voltage. I still feel uncomfortable running too many 7V things off the 12/5V split from the power supply since potentially I could feed back voltage to the PSU since less and less components are using 5V. The zalman fanmate was great apart from the fact it didn't let you turn it up to maximum voltage since there was always a drop. And pwm has failed to impress me on most fans I've used it on so it's something I basically never use except for one unusual fan I got in the past that seems to love it.

So what is my conclusion? Compared to the reference? The Nexus 120mm is a more versatile fan overall since its flow has greater flexibility at different voltages and can reach higher levels but at equivalent revolutions there is barely anything to distinguish them. There is great appeal in a fan that is working at the manufacturer's settings and achieves noise levels I desire. There is also the theoretical longevity advantage of the bearings, and the open corners that don't require cutting. Conclusion is that if you do not want to fiddle with voltage and want something below the noise level of other components, then this is the fan for you. Otherwise get a Nexus. In Australia, at least, these fans are priced almost the same.

[andyb]

Nice review, I am looking forward to the SPCR face off of 120mm fans, both the Nexus, and various S-Flex fans will be involved.

I got a 1200rpm S-Flex with my Ninja, and just like the 800rpm model you have got, it buzzes, ticks, and clicks very annoyingly, unfortunatly I dont have a molex ---> 3pin adaptor to test it at a set voltage, so I have never been able to compare it to my Nexus's (or are the called "Nexi"???).

I also find a nexus @ 12v loud, but at 5v, they are whisper quiet (not silent) and very very smooth, I have to concentrate to hear them, and even then i am not sure if its my imagination, I am guessing that they are running @600rpm.


Andy

[sjschwinn]

A zalman fan mate was a decent match for it, but could easily drop it to a speed below which it refused to turn.

..

So what is my conclusion? Compared to the reference? The Nexus 120mm ... at equivalent revolutions there is barely anything to distinguish them. ... There is also the theoretical longevity advantage of the bearings

Nice review. I also just purchased the S-Flex D, and have a few additional comments.

I have also tried running it with a Fanmate, and although I haven't checked the actual voltages, I can run the fanmate all the way down to it's lowest setting - even while running 2 other fans in parallel - and although it won't start at that voltage, it runs just fine there.

I do agree with the rest of your review. I find that although it's not quite as smooth sounding as the Nexus or YL, the motor/bearing noise was as non-irritating as any other fan I've tried (and I've tried several of the recommended fans here). It was noticeably better than the GlobalWin 120mm that I've seen recommended around here (which is actually a decent fan), which I bought at the same time.

Lastly, the comment on the longevity is why I decided to purchase this fan. I plan on installing it blowing downward in my P180, and I didn't like the idea of running any of the sleeve bearing fans in that orientation (many of which make more noise in that orientation anyway).

[sjschwinn]

I got a 1200rpm S-Flex with my Ninja, and just like the 800rpm model you have got, it buzzes, ticks, and clicks very annoyingly, unfortunatly I dont have a molex ---> 3pin adaptor to test it at a set voltage, so I have never been able to compare it to my Nexus's (or are the called "Nexi"???).

Are you referring to the fan included with the Ninja Plus? I have the Ninja Plus, and I'm almost certain the fan that was included with it was NOT the S-Flex. (I'm not using that fan, BTW.)

[Felger Carbon]

Are you referring to the fan included with the Ninja Plus? I have the Ninja Plus, and I'm almost certain the fan that was included with it was NOT the S-Flex. (I'm not using that fan, BTW.)

I own both fans (SFlex E, NJ+) and I'm sure they aren't the same fan. But amazingly, the motor noise sounds exactly the same, both in volume and in character (frequency characteristics). Blindfolded and just listening, I'd defy you to tell the difference! BTW, this NJ+ is not the rev B fan.

[andyb]

It's NOT an S-Flex like I thought, and it did come as part of the Ninja Plus bundle.

Its a scythe branded, AD1212DS-A73GL(6TCL3)
DC 12v @ 0.13A

I got confused because the Plus version of the Ninja came out at about the same time as the S-Flex so I put 2 and 2 together and got a crap fan.


Andy

[NeilBlanchard]

Hello,

The number of Scythe models is fairly confusing. I have only used the Scythe DF (by Young Lin), which is being discontinued. It is a 1200RPM model, and it is slightly quieter than the GlobalWin NCB (which has/had a very mild bearing noise). Both were much quieter than a low speed Yate Loon.

The "8.7dBA" rating might be a little more believable with a 1 in front of it, but even 18.7dBA (@ 12v) would be a virtually silent fan.

[ckolivas]

Yes I would say 18.7dB is probably close to what this fan sounds like given comparisons with other fans. Probably the best thing I can say about the sflex D is it is the quietest available 120mm fan on the market... but then it is also the lowest flow. As regular SPCRers know, though, it is the only way since the laws of physics still need to be obeyed

[nightmorph]

--

[ckolivas]

Heh that can't be good. The fans that come with the heatsinks aren't the same as the s-flex.

Also it's nice that the recent 120mm fan roundup by SPCR agrees with what I've said here about this fan.
http://www.silentpcreview.com/article695-page5.html

[nightmorph]

--

[ckolivas]

(Offtopic: didn't know you hung out here. We quite like ck-sources over at Gentoo. )

Thanks

(/offtopic)
You might like my recent addition then:
viewtopic.php?t=36474

[sjschwinn]

so there's not as much reason to choose it over the Nexus, in my opinion.

The reason I chose the S-Flex was for the non-sleeve bearing for use in a "blow-up" or "blow-down" orientation. In my experience with sleeve bearing fans, when placed in that orientation they don't sound nearly as good, and the longevity/durability is very poor. The S-Flex should stay quiet much longer than the Nexus in a horizontal orientation. (Another example of this is when Seasonic went with the Adda ball-bearing fans over the YLs in their PSUs due to durability issues.)

[ckolivas]

I agree. The value of the SFD bearings has not been emphasised enough in most of these comparisons (except by the SPCR crew) where the extra flexibility of possible usage applications and the potentially much longer life expectancy are of great value. Especially considering all of my pcs are on 24/7.

nightmorph I forgot to say I've been thankful for the gentoo community over the years for the extensive testing they've done on my patchset and the feedback I've gotten. If ever there was one failing on their part it was the preoccupation with merging patchsets of early code which then ends up being 1. a bad advertisement for the early code in question 2. provides no direct reliable path for feedback/bug reports to the original coders and 3. because of inappropriate merging the code is not being properly tested. Nonetheless the community's interest in new and exciting code has made for a great testing ground for kernel hackers.