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Old November 6, 2007, 09:52 AM
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Default Reviewer Tryouts: Scythe SFF21F



Reviewer Tryouts: Scythe S-FLEX SFF21F 120mm Fan Review


Scythe S-FLEX SFF21F 120mm Fan
Price: $14.99 at NCIX Canada
Availability: In Stores now
Manufacturer’s Part Number: SFF21F
Warranty: 1 Year Limited


Table of Contents


1. Introduction
2. Packaging
3. Features & Specifications
4. Modding Options

5. Testing Methodology
5A) Subjective Tests
5B) Effects on Hard Drives
5C) Effects on Passively Cooled GPU
5D) Effects on Passively Cooled Motherboard
6. Longevity

7. Conclusions


1 – Introduction
Scythe have in very short period of time made quite the name for themselves with their S-Flex 120mm fans. Today I will be looking at the enthusiast model or as Scythe call it the SFF21F. To the average computer buying public the name “Scythe” probably doesn’t conjure up any images and they probably have never even heard of the company. However if you say “Sony” you then have their attention. Like many fans makers Scythe actually doesn’t manufacture their own fans; rather they subcontract the actual production to other companies. Some reports that I have read state they are made by Sony themselves, others say it is Adda. Regardless of who is actually making it, this fan is using Sony’s “S-FDB” Fluid Dynamic Bearing technology.

Is this a good thing that it’s based on Sony technology? If you can get past all the blunders Sony Corp International has made recently you will see that their engineering section is still considered one of the best in the world. The main advantages FDB’s have over normal sleeved or ball bearings is that they create very little friction and very little noise. This is because the two main moving parts are separated not by grease or ball bearings but by FLUID and fluid has a tendency to dampen any noises the bearing surfaces make. The easiest way to think of how a FDB system works is to take a normal “sleeved” bearing design and replace the grease with fluid. Some people refer to fluid dynamic bearings as a modified sleeve design. Whatever else you call it, you can call quiet.

Here is a picture of how a FDB works (taken from back of the Scythe box, enlarged and edited w/ Photoshop):



With such a prestigious pedigree behind them does this fan live up to expectations? More importantly how does it compare to a regular “value added” dual ball bearing fan like the Antec Tricool? Let’s find out!

2- Packaging



As you can see in the pictures above the packaging is very sparse. A basic plastic see-through container with a cardboard liner is all it is. It doesn’t have any flashy graphics like some companies have, and except for a silver sticker that is mainly in what appears to be multiple Asian horizontal scripts it is almost drab in appearance. As for the sticker, whether it is in Chinese hengpai style + Japanese yokogumi style or some other mixture I can not tell you. To me it one line looks like Japanese Kana and another looks like Chinese Kanji. All lines appear to be written in a horizontal style with the bottom two lines being in English.



While the outside package maybe sparse the contents of the box are not. Scythe includes a 3 to 4 pin connector that will still allow you to see how fast your fan is spinning (via 3rd wire 3pin connector off shoot). As an added bonus they included 4 standard mounting screws. This of course is an expected addition considering the price of this fan, but it is nice to see that they did not overlook the basics.

3- Features & Specifications
This fan (also known as the “F” Model) is a 120mm, 7 blade fan that is rated to spin at 1600 rpm. At this speed it can move over 63.7cubic feet of air per minute and is rated to it at 28 decibels. This is high CFM / low dba is accomplished solely by using Sony’s Fluid Dynamic Bearings and is not due to any exotic shaped blades like other companies use.

As for construction, Scythe opted for a fairly standard all black plastic body with the more common “flange style” mounting bracket holes. What this means is that the corner holes are not connected from front to back (i.e. there is no “tunnel”) this makes using vibration reducing rubber pins much easier.

While there are 3 different models of the S-Flex they are basically the same fan, the only difference is the speed at which they rotate.

The Model D spins at 800rpm and moves 33.5 CFM @ 8.7 DBA
The Model E spins at 1200rpm and moves 49 CFM @ 21DBA
The Model F spins at 1600rpm and move 63.7CFM @ 28DBA

For comparison here are the specifications for the Antec Tricool:
Low setting 25 DBA, 39 CFM
Medium setting 28 DBA, 56 CFM
High setting 30DBA, 79CFM

On paper the Antec Tricool fans (that came free with my Antec SLK 3000b) case are louder but they also move more air. It will be interesting to see if this translates to real world performance gains.

Here is a graph showing the relationship between noise and air movement. It is done it a CFM per 1 decibel format.


One nice feature that all 3 models of Scythe’s have is what I like to call “ear saving technology”. When something obstructs a fan blade(s) the fan automatically stops rotating. Even better, is when the obstruction is removed the fan will restart itself. In practical term this means when you stick your ear accidentally in a D model, say while listening to it to make sure its actually working, it will stop before doing any damage and then restart itself after you curse and jump back (thus pulling your unbruised ear but badly battered ego away). Yes they are that silent. I have seen numerous people stick their fingers in the spinning E models but I think I am the only one foolish enough to have stuck their ear in one. Worse still is that I did it in front of witnesses. As for the F model it is noticeable, and you can tell when it is on. However, the type of noise it produces is very low key and mainly comprised of wind noise.

4 – Modding Options

In an effort to "improve" the noise level of a fan, a person of moderate skill and knowledge can easily modify it to run slower. By running at a lower speed a fan WILL move less air but it will also make less noise. These easy modifications I am referring to are the "7 volt mod" and the "5 volt mod". Both will allow a standard 12volt fan to run at either 7 volts or 5 volts respectively. Both of course usually require the use of a standard 3 pin to 4 pin molex converter. Some fans come standard with a 4 pin connector but even on these I prefer to mod and use a removable 4 pin molex extender. That way I can easily swap out a 7 volt for a 5 volt mod and as an added bonus when the fan dies I can reuse the modded extender on the new fan.

The skill comes into play when changing pin headers. You have to gently close the "wings" on the plunger connectors enough to remove them from the plastic Molex connector block, making sure not to crush them or close them sp much that when you open them back up they break. Alternately, you can simply cut them off, pull out the plungers, restrip the wires and reattach the pins (or use new ones). Either way you have to be confident enough in yourself to try it.

Before modern fans were common, this trick was very common. However, I think there usefulness has been greatly reduced by the introduction of variable speed fans (such as the Tricool) and variable speed fan controllers. Both of which require no modifications and have none of the potential negative effects these two modifications can have.




As you can see in the above picture this what a unmodified fan connector looks like.

Here is an asci breakdown of the picture.


7 volt modification

In my opinion the 7 volt modification is the more dangerous of the two and does require a higher level of knowledge. In essence your fan will draw power from the 12volt positive line and feed it back INTO the 5 volt positive line. This can harm your power supply unless you are very careful. You have to add in devices further down the line that USES more 5 volts than the 7 volt modded fan puts out onto the rail. As you can imagine it gets more and more complicated as the number of 7 volt modded fans increases. When I had to use the 7 volt mod I liked to add in a 5volt modded fan further down on the rail line. This way I know that no volts would be going back to the power supply.



Here is asci schematic breakdown of the above picture


5 volt modification
The 5 volt modification is a much more sane and intuitive modification. By simply swapping the 12v positive and negative for their 5 volt counterparts you easily get a fan that runs at 5 volts. There are no negative side effects associated with this modification other than the greatly reduced air flow. Due to the drastically reduced air flow this mod is only recommended for cases with multiple fans. For example the CoolerMaster Stacker 830 can have up to 9 fans installed. In my opinion 9 fans running at 5 volts each still provides more air flow than many other cases provide with two 12 volt fans.



Here is an asci schematic breakdown of the above picture




You can see the results of modding the Scythe later on in this review.

I can tell you that the Antec Tricool was the more user friendly of the two. This is due to the simple fact that modding of the fan was not necessary. By simply changing the switch position, I could easily decrease the fan speed. Please do not get me wrong, the Scythe was as easy as any fan to mod, it is just that not having to do it is the easiest of all.


5 – Testing Methodology and Results

As with any mass produced piece of equipment variances will be found from batch to batch. These are just the findings that I found on a very small sample size of the given products. I have personally used both of these fans in my builds, and consider them both to be good choices with their own list of “pros and cons”. Please do not let 1 or 2 degree separation sway your decision, as this is well within manufacturer’s tolerances.

Due to its nearly all passively cooled hardware I opted to use my older test bed system for this review:

Test Computer:
AMD 4400+ w/ mild OC of 2.4ghz ((AMDs Heatpipe heatsink +fan combo)
Asus M32N-sli deluxe
2 gb Corsair XMS pc3200
ANTEC SLK3000B ATX MID TOWER CASE
2 Seagate Barracuda 7200.10 320GB
2 WD SE 120gb
1 WD Se 200 Gb
600 Watt Seasonic S12
Antec SLK3000B case with 1 120mm fan port for intake and 1 120mm fan port for air outtake.

Ambient Room temperature was 20 degrees Celsius during testing.
12 volt rails were measured at 11.94V with a voltmeter at the point where fan(s) were to be connected.
5 volt rails were measured at 5.03V with a voltmeter at the point where the fan(s) were to be connected.
Since this pc case uses 2 fans for cooling I obtained 2 fans of each brand. When any test was done only that brand was in use. This was done to remove any possible skewing of data due to external uncontrolled variables.


5A) Subjective Tests
Subjective Tests:
These test are the 3 main tests I do on any fan I am planning on using in a build. If they don’t sound or feel "right" I bin them and use alternatives. Whether that means a completely different brand or just another one from a different batch greatly depends on the priorities of the build (i.e. noise vs. performance vs. longevity vs. style).

Finger Spin Test:
Just as the name suggests I give the unplugged fan a quick spin with my right hand index finger while holding it vertically in my left. This is done to see how much friction a fan produces (via length of time it take to stop and perceived speed at which it rotates); but mainly it is done to fell how well balanced a fan is. If a fan feels unstable then it is most likely unbalanced and will have a drastically reduced life expectancy and may catastrophically fail taking other computer parts with it.

Both felt well balanced but the Scythe seemed to spin faster and longer that the Tricool.

Noise and Vibration:
While holding the fan in my left hand, I plug in the fan and then turn on the computer. I feel for any vibration and listen for any noise. I do this while holding the fan horizontally, vertically, and at an approximate 45 degree off vertical axis tilt.

The Scythe once again is very quiet but was slightly noisier when held horizontally. When held off axis it was produced even more noise and vibrated much more. At 7 volts it was whisper quiet and at 5 volts it was below ambient noise levels. The vibrations felt when held off balance were greatly reduced at 7 and were almost non-existent at 5.

I found the Antec noisy when on high speed regardless of its orientation. At medium speeds the noise level is more tolerable and at low it is almost as good as the (scythe at 12v). As for vibration, it exhibited typical dual ball bearing vibration but it was more tolerant of off axis orientation than the Scythe.

Weight and construction:
This test consists mainly on how it "feels" sturdy or flimsy in my hands.

Both the Scythe and the Antec fans felt sturdy. If I had to pick one based on construction I would chose the Antec. It felt sturdy and the 3 position switch is well thought out (if a little short in length of cable). Not having to mess with moving cable pins to change speeds is a nice bonus.

Please note: These test are highly subjective and are not included in my final analysis of the fans they are simply included for illustrative purposes only.
5B) Effects on Actively Cooled Hard Drives
The cooling design of the Antec case incorporates active cooling of the hard drives by the simple yet effect method of placing the hard drive cage directly behind the front intake fan. Since this means that the hard drives temperatures will be directly affected by the amount of air moving past them; a simple stress test of the hard drives will show how effective the fan is at moving air.
Before starting the test I loaded SpeedFan to see what idle temps of my hard drives were, I then created a folder on each hard drive called smallREAD and a folder called smallWrite. I then placed 4gb of random length files in the smallRead folder. No file was over 4megs and no file was smaller than 32k.
I then created a folder on each hard drive called LargeRead and LargeWrite. In the LargeRead folder I placed a single large 3.7gb rar file (it was actually a rar'ed archived version of the smallRead folder plus some other files to pad the size).
After this was done I let the system sit idle for a half hour to let the hard drives go back to normal operating temperatures as recorded before the tests took place. These temps are listed as my baseline “idle temps” in the graphs.

I then ran a simple batch file that would first copy the contents of SmallRead folder from D to E drive’s SmallWrite folder. While this would be taking place, hard drive F would be copying its SmallRead folder to G’s SmallWrite folder, AND D would be copying Gs SmallRead folder to its own SmallWrite Folder.
When this was completed I recorded the temperatures of the hard drives. I then redid the same test but used each drives LargeRead and LargeWrite folder.
An easy way to picture how this test was done is to visual it as such
D->E->F->G->D
If there were any variances in temperatures between the two tests, I recorded the greater temperature. All Power saving features, including powering down of individual hard drives was disabled for all tests. At no time did I include the OS drive in this test. The OS drive resides in its own 5.25 bay cooler and as such would skew the results. For this reason you will only 1 Seagate barracuda 7200.10 included in the results.








As you can see from the above graph the Antec Tricool on its highest speed did better than the Scythe. However, its noise level was also higher.
At there slowest speed both fans created temperature readings above my comfort zone; and I would not consider either of these fans to be effective cooling solutions at those levels. I don’t have any serious concerns about the long term effects these elevated temperatures would have on the hard drives but I just prefer to have my hard drives run cooler than 40+ Celsius.

5C) Effects on Passively Cooled GPU
The video card used for this test is an older Evga 6200 that is passively cooled. Since there is no moving fan to actively cool it, it just like the hard drives relies solely on air movement inside the case to keep it cool. In practical terms this means any variances from fan to fan will become quickly apparent when the video card is stressed.
The only modification done to this 6200 was that approximately 3000 hours ago I removed the heatsink, removed all the older thermal interface media and applied a thin layer of Artic Silver 5 to it. I also gently lapped the bottom of the heatsink before reapplying it. This dropped its normal idle temperature from 47 to 39 Celsius.
Before starting the tests I let the system sit idle for half an hour and then using the Nivdia control panel I recorded the temperature displayed. This is the idle temperature listed in the graphs. To stress the GPU I ran ATI Artifact Tool for 30 minutes. At the end of the 30 minutes I recorded the highest temperature displayed. I then shut the system down, swapped out the fans, turned the system back on and after letting the system sit for another 30 minutes, I took note of the idle temperature and then redid the test. Once again noting highest temperature displayed.

Both Fans performed admirably well at 12volts. At 7 volts for the Scythe and middle setting for the Antec, the Tricool was better but was once again was more noticeable. After 5 minutes running the test with Antec Tricool’s on their lowest speed I stopped the test fearing for the safety of the video card. After only 5 minutes the temperature had quickly passed 80 Celsius. They same thing happened when I tried with a 5 volt modded Scythe, except that it went up even faster. Just as with the hard drive tests, neither fan at their lowest speed has shown itself to be a viable long term cooling solution for this kind of system.

5D) Effects on Passively Cooled Motherboard


Picture courtesy of Asus’s Website

As you can see in the above picture the motherboard that I used was an Asus A8N32-SLI deluxe. It has no active cooling to keep its Northbridge or Southbridge cool, rather it has a heatpipe + heatsink combo that relies on air movement to keep them cool. The only modification to this motherboard was that approximately 7000 hours ago I removed the heatpipe/heatsink combo and replaced the Thermal Interface Media with Artic Silver 5. After approximately 200 hours it had dropped temperatures by nearly 5 degrees.

While testing both the hard drives and the graphics card I also took note of the motherboard temperatures. All temperatures recorded were taken from SpeedFan and are the highest IDLE and Active temperatures that were recorded.

Due to the fact that not all tests were completed I have not included the incomplete results for either fan at their slowest speed.



As you can see the Antec once again provided better cooling. This is not surprising as it does move more air than the Scythe.

6 – Longevity
As silent pc enthusiasts have always known, sleeved bearing fans can be much more silent than their ball bearing counterparts. However, this reduce noise level was balanced against a much shorter life expectancy and this is where FDB’s really shine. Not only are they by there very nature quiet, they are also extremely durable. All 3 models of Scythe SSF21s are rated at a Mean Time Before Failure of 150,000 hours, or over 17 years. This is astounding especially when compared with the usual MTBF of 10,000-30000 hours for sleeved, and just 60,000 – 100, 000 for various dual ball bearing designs.

Before I continue, I would like to state that MTBF numbers are not the same as “expected time before failure”. All MTBF really mean is that if you have a MTBF of 150 000 AND you USE 150 000 you can expect 1 to die every hour. It does not mean that ANY will LAST 150 000 hours…a subtle distinction but it is a distinction you shouldn’t overlook.

Unfortunately, manufacturers don’t like to publish the life expectancy of their product. This would give customers a false sense of security, and (where we do live in a litigious society) this “level of expectation” would leave them wide open to a class action suit. After all if they say it “should last X hours” and when a good percentage do not last that long, well lets just say that is the stuff lawyers dreams are made of.

To get a better “feel” for what the manufacturer thinks is the real length of time a product should last simply look at the length of warranty. The length of warranty has been calculated to be long enough that customer feel secure in purchasing it BUT still short enough that it will be “out of warranty” when most fail. Taken for what its worth, Scythe’s come with a 2 year warranty and Antec comes with a 3 year warranty.

On a personal note:
I have been running 8 Model E’s 24/7 in my CoolerMaster Stacker 830 for over 10,000 hours now. While this is less than 7% of their MTBF, what I can tell you is that they are as quiet and efficient today as they were a year and a half ago.

In contrast to this I have used various sleeved bearing brands in the past and usually by this time I start to notice degradation in their quality. It usually starts out with fine “graphite” like particles around the fan engine housing and gets worse from there as time goes on.

To put it another way the Scythe’s “just work”. You don’t have to tinker/tap/mod or even “oil” them every to get their best from them.

7 – Conclusions
On paper the Antec is a much better fan pushing nearly 24% more air than the fastest Scythe. However, in real world testing it was only slightly better that the slower and quieter Scythe. On paper the high frequency bearing noise that the Antec Trciool’s exhibit may only be a few decibels higher, but in the real world it was much more noticeable. While testing was taking place the Scythe’s fan noise was easily covered by normal background noise. This did not happen with the Antec Tricool’s. Only by turning up the volume of my speakers was I able to cover the noise they generated.

If I had to choose one over the other I would readily choose the Scythe. I am willing to work around a slightly lower cooling efficiency if the amount of noise is also markedly decreased. While yes the Tricool is speed adjustable, I do not think it is very efficient on its slowest speed and on its highest speed it produces to much bearing noise for my comfort level. To put it another way this is a classic example of a “Jack of All trades, Master of None” being outclassed by a highly refined “Expert of One”.

The only concern I have regarding the Scythe fans is their price. At nearly $15 each they are NOT cheap. If cost is a major consideration then the Antec is a much more sensible option for cost conscience consumers. It sells for nearly half the cost of a Scythe and comes with a 3 year warranty.

Scythe F model 4.2 out of 5 with reservations.
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Last edited by AkG; November 7, 2007 at 10:01 AM. Reason: Fixed ASCI "graphs"
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