PWM fans for Push/Pull

[figment]

I've pretty much settled on the Thermalright Venomous-X for my upcoming i5-2500K build. The location where it will sit has some natural sound dampening characteristics, but not the best air-flow, so I'm using a higher airflow case (CM 690 II or Arc Midi... if they ever show up). I'm hoping to be able to get a 24/7 overclock of 4.5GHz, but I'm also somewhat temperature averse on my CPU, hence the aggressive cooler on a Sandy Bridge chip. I'm trying to stick with PWM fans to give me motherboard control for a really quiet idle. I'm okay if its a little more noisy under load.

First question is: What PWM fan(s) should I use?

Slipstream PWM : Tried and true.
Kama Flex PWM : Better static pressure, supposedly
Noiseblocker BlackSilent XLP : Seems to be recommended by a lot of people.
Something else?

Second question: Is there any reason not to put both PWMs on a splitter so they match RPM. I assume matched-RPM would be the best way to go here.

Looking at the fan options, I'd only be worried about the Noiseblockers, as they report they can pull up to 0.4A, and ASUS says the CPU fan header is rated for 1.0A. Both of the Scythe fans report current ratings of <0.2A so there shouldn't be much trouble there.

This will be set up in a front-to-back orientation, and there will be another fan in the back helping to push air out of the case, so I suppose one possible response would be: "You're wasting your time/money on push/pull." I'm okay with the cost of an extra fan, so long as it actually produces better results, and that would be either lower temps or the ability to keep the PWM duty cycle down <40% for the majority of the load range.

Anyone want to share some wisdom?

[lodestar]

The Akasa AK-CB002 PWM fan splitter cable http://www.akasa.com.tw/update.php?tpl= ... l=AK-CB002 draws power directly from the PSU and only takes the control signal from the motherboard CPU PWM fan header. This allows a free choice of PWM fans without being concerned about the power draw.

The other option that might be worth considering is to put a single CPU PWM fan plus an exhaust PWM fan on the splitter cable, or two CPU PWM fans in push-pull plus an exhaust PWM fan. I have used the first option on several systems with the Slipstream fan, and you will certainly get a very quiet idle a 400-500 rpm. The advantage of the CPU/exhaust combo is that it will automatically increase fan rpm and case airflow under load (particularly from high performance gaming cards), and drop back to a quiet idle again when the load is removed.

[lodestar]

It might be worth adding that a PWM fan splitter only reads/reports the fan rpm from one fan, normally the CPU fan. I am not a gamer but I do build/modify systems for my gaming relatives. On a Core i7 1366 system with a top end graphics card used to play the original Crysis I saw a fairly rapid rise in PWM fan rpms from 500 at idle to 1100 under load. So a PWM fan with a top speed of 1200/1300 like the Slipstream ought to be sufficient in most cases.

[figment]

The Akasa AK-CB002 PWM fan splitter cable http://www.akasa.com.tw/update.php?tpl= ... l=AK-CB002 draws power directly from the PSU and only take the control signal from the motherboard CPU PWM fan header.

Yeah, I would consider that if I go with the noiseblockers.

The other option that might be worth considering is to put a single CPU PWM fan plus an exhaust PWM fan on the splitter cable, or two CPU PWM fans in push-pull plus an exhaust PWM fan.

I thought about that, but I'm wary of tying the main exhaust fan to the same PWM signal of the CPU fan. The CPU fan will be controlled by CPU temperature, but that might not track with the overall system temperature. I'll have an MSI GTX-560 which vents much of its heat back into the case, so I need the exhaust to ramp up when the GPU is stressed but the CPU is not.

It might be worth adding that a PWM fan splitter only reads/reports the fan rpm from one fan, normally the CPU fan.

Indeed. That's why you should always get purpose-built PWM splitters. They (effectively) cut the Sense lead to one of the fans, so that two Sense signals don't interfere with each other.

I am not a gamer but I do build/modify systems for my gaming relatives. On a Core i7 1366 system with a top end graphics card used to play the original Crysis I saw a fairly rapid rise in PWM fan rpms from 500 at idle to 1100 under load. So a PWM fan with a top speed of 1200/1300 like the Slipstream ought to be sufficient in most cases.

The P8P67s let you set up fairly detailed duty-cycle ramps, so I'll be able to control just how the speed increases. All of the fans I listed above are in that 800-1500rpm range, because my experiences match yours. It's just a question of which ones to buy.

If there's no real difference, then I'll flip some coins or something. Or perhaps I'll give the noiseblockers a try, just to experiment.

[ces]

Slipstream PWM : Tried and true.

The only PWM fans that seem to consistently get applauded are the slipstream ones. I seem to recollect that SPCR a long time ago made a comment on the Scythe Flex PWM and/or the Nexus PWM in the context that at that time they hadn't found any PWM fans they liked. Apparently it is harder to make a quiet PWM fan than a normal fan.

Arctic cooling has PWM fans that have daisy chaining built in to them. I think you can daisy chain 3 of them if you want to... maybe more.

Hopefully in SPCR's next fan testing cycle they will test some PWM fans. But for the moment you will just have to experiment on your own. The slipstreams seem like a nice place to start. Arctic Cooling would be worth a look. And why not the Akasa Apache. You can buy one of each. Try them. Then select which one to double up on.

Noiseblocker is a good brand. I have never seen anything good or bad about their PWM models though.

Would you be kind enough to report back and let us know what happens. What works for you and what doesn't.

[ces]

I am going to have to correct myself on my recollection of SPCR on PWM Fans.

In their 1998 Scythe Roundup, they have some very very kind words to say about the Scythe Kama PWM
http://www.silentpcreview.com/article83 ... l#KAMA-PWM

I got all three Nexus PWM fans (80, 92, 120) and compared them with the classic ones. I even rigged them up side by side outside the computer and made sound recordings to try and determine differences. I drove all fans from my ASUS MB and checked RPM with Speedfan. However, it was difficult to draw scientific conclusions with this limited methodoly.

The new fans have higher RPM for the same voltage so they have a higher capacity when called for. When turned down to the same flow, they sound about the same. I tried to gauge flow both subjectively and with a simple device. All in all, I would say that the new fans are not more quiet than the old ones. Perhaps about the same for the same flow.

I had no problem with whine with any of the PWM fans. I never published any recordings because when I got to the 80 mm tests, I run into some vibration induced noise and realized I had to re-make the whole setup to eliminate this problem. I also never figured out a good microphone placement. If I don't place the mic on front of the fan, it won't capture the right sound. However, when I do, most of the picked up sound is noise from air hitting the mic and not the sound from the fan.

This comment is about an 80mm Nexus PWM:

So finally I have gotten my new Nexus PWM fan installed in my new ATX case Here follows non technical and subjective information:

1. A little about my current setup
Since it's a PWM fan, I decided to connect my ZALMAN CPU cooler to a conventional 3-pin case fan connector on the motherboard and have the Nexus PWM fan connect to the CPU fan connection for full PWM functionality. My ATX case, the Super Flower SF-201T3-BK, has a total of five places for fans (all 80mm; two in front, two in back and a single one exactly in the middle of the top panel). The Nexus PWM is mounted in the top to help exhausting air along with the PSU fan.

2. Noise?
(ASUS P5K WS motherboard). In the BIOS, I have set the ASUS Q-Fan feature to enabled for the CPU fan. I also set the CPU fan type to PWM and the fan profile to Silent. The Nexus PWM fan operates at roughly 1200RPM with the Silent profile, around 1500RPM with Optimal and 2000RPM with Performance profiles. In Silent mode the fan actually is quite quiet. I can't say it is silent. My PSU has a much more quieter fan (some ADDA fan, it's the Nexus NX-8040) so maybe the experts can make a good guess in dBA on how noisy the Nexus is at 1200RPM. When using Optimal profile, the fan is VERY audible. It makes a lot of noise and the difference is only a pitiful 300RPM! In Performance mode... CHEESH! Even my DVD drive spinning a DVD at 20x speed sounds quieter!!!

3. Vibration?
The Nexus came with silicone fan mounts. And that for a good reason. The fan VIBRATES like hell! Do you know these devices which massage your back or those small pool like things were you put your feet in warm water which get massaged with mega vibration? This fan vibrates just as much! It is a requirement to use the silicone fan mounts or else your PC will vibrate like a monster and make more useless sounds!

4. How much air will it push in or out?
With Silent profile it rotates at 1200RPM, so it should move a little air. Notice that the maximum airflow in CFM is noted at Nexus' website. I don't have any meters or know the calculations to give you any CFM numbers, but by placing my hand on the fan (the air is coming up facing my hand), I feel very little air that comes out.

5. Is it a good buy?
Stay away. The Nexus Basic 80mm case fan is much better, can rotate at higher RPM than the PWM while still making less noise and of course pushing much more air than the PWM one (also the Basic vibrate sMUCH less than the PWM!). One thing that is very annoying about PWM fans is that they spin up ultra fast when booting up your system and then slowly go down in speed. It makes you get disturbed or at least it made me get disturbed every time I powered on the PC.

6. Whining?
Many users have reported that PWM fans suffer from whining. The Nexus PWM does whine a bit, but only a bit. It is noticeable only when being very near to the fan, but at 20-30cm away from the fan the whine is not that noticeable, but it is there.

7. So after all this nonsense what do you say about PWM fans?
They are becoming increasingly popular, but with most motherboards limited to a single PWM connection and the fact that (at least the Nexus) PWM fans make whine and more vibration than their "normal" DC counterparts, I doubt any silent computing enthusiast will buy a PWM fan. I say it straight: they suck. Who cares if the fan is auto controlled? Just move your ass and go buy a fan controller then hook up your case fans to the controller and put the speed manually up and down. Of course if you're like me and hate dangling cables then you might as well buy 3-pin to 3-pin voltage reducing adapters like ZALMAN RC-100 which makes 12V to approx. 5.5V (In combination with my ZALMAN CNPS-7000C CPU cooler, the fan on the ZALMAN spins at around 1000RPM and is NEAR INAUDIBLE level! And the CPU still is cool at around 38C when idling!)

Here is a 4 page thread on the topic of: Which is the quietest 120mm PWM fan?
viewtopic.php?f=9&t=54662
(a lot of respected and thoughtful posters and posts and some kind words for the Akasa)

I still think you are going to have to do your own testing and experimentation.

[figment]

Yes, but those comments are from 1998. The Scythe Kama Flex PWM (SA1225FDB12H-P) is not the same fan as the Scythe Kama PWM (DFS122512L-PWM), and the Slipstream PWM was just becoming available in 2008. The Noiseblockers weren't really widely known.

PWM is still gaining in popularity and the enthusiast market rarely seems eager to embrace technology that sacrifices raw ability for quiet or efficient operation. That's what makes SPCR unique.

At the moment, I'm thinking I might give the Noiseblockers a try, just because they seem to review well and there aren't many people around here who seem to have experience with them. I'm fine with trying them out and posting a mini-review.

[fumino]

check out the scythe mugen-2 review to hear spcrs take on the slipstream pwm.

[ces]

Yes, but those comments are from 1998. The Scythe Kama Flex PWM (SA1225FDB12H-P) is not the same fan as the Scythe Kama PWM (DFS122512L-PWM), and the Slipstream PWM was just becoming available in 2008.

That was all I found on SPCR. It is an imperfect world with imperfect information.

I don't think I trust non-SPCR reviews of PWM fans. I think the sound issue with them and their variable speed is just too complex to rely on testing done by some overclocker or water cooler site review.

I'll look forward to what you find with the Noiseblockers. I have a 140mm noiseblocker and I like it. Please don't forget to post what you learn.

[ces]

I've pretty much settled on the Thermalright Venomous-X for my upcoming i5-2500K build.

You could just as easily have chosen the Prolimatech. What made you chose the Venomous-X?

Sooner or later I will be building a 2600K. I am probably going to use the new 140MM Noctua downdraft... stuffing it into a Lian Li Q07 using an external PSU (to make room for the cooler). But I was thinking maybe about the Prolimatech. I wasn't really thinking about the Venomous-X. Just wondered why you chose it.

In my case I will experiment. If the noiseblocker pwms work for you, I might try them. But I will probably start off with a single 800 rpm slipstream running at a steady 12v. That may be all that I need... even while benchmarking.

[ces]

Noiseblocker BlackSilent XLP = 1000-2000 rpm
http://www.noiseblocker.de/Datenblaette ... _de_en.pdf

NB-Multiframe M-12p = 1000-2000 rpm
http://www.noiseblocker.de/Datenblaette ... _de_en.pdf

NB-Multiframe M-12ps = 600-1500 rpm
http://www.noiseblocker.de/Datenblaette ... _de_en.pdf

Scythe Slipstream PWM SY1225SL12LM-P = 324 ~ 1,200 rpm (±10%) or 0 (+200)rpm - 1.300 (±10%) rpm (depending)
http://www.silentpcreview.com/article961-page1.html
http://www.silentpcreview.com/article961-page5.html
http://www.scythe-usa.com/product/acc/0 ... etail.html
http://www.newegg.com/Product/Product.a ... 6835185144
http://www.frozencpu.com/products/10026 ... 2LM-P.html

Akasa 12cm APACHE Black = 600 -1300 rpm
http://www.akasa.com.tw/update.php?tpl= ... l=AK-FN058

Seems like the NB-Multiframe M-12ps or the Slipstream might be the safest choice if sound is your preeminent consideration. The other two Noiseblockers can slow only to 1000 rpm. No matter how well they are designed and constructed, it is going to be hard for them to match a NB-Multiframe M-12ps at 600 rpm or a slipstream at under 500 rpm.

Dual fans on such a powerful cooler will probably almost always be running at their minimum speed. The slipstream specs are sort of interesting. I wonder what that 0 rpm means in real life operation?

[figment]

I don't think I trust non-SPCR reviews of PWM fans.

Neither do I, and that's the problem. There hasn't been a (recent) fan review from SPCR (not blaming Mike) for a long time, and I don't think there's ever really been a good PWM review. There are only a couple other places that I could moderately trust, and I managed to find a few youtube videos that at least let me hear the fans for myself.

The Noiseblockers as a group seem to have a lower tonal noise than the Gentle Typhoons and some of the other fans. That should work a little better for me.

I'll look forward to what you find with the Noiseblockers. I have a 140mm noiseblocker and I like it. Please don't forget to post what you learn.

Definitely. And if they don't work out, I'll do a comparison with the fans that I replace them with.

You could just as easily have chosen the Prolimatech. What made you chose the Venomous-X?

The other options were the Megahalems, the Hyper 212 and the Titan Fenrir. I considered the TR Archon and MUX-120 for a bit, but the Archon seemed to be more than I needed and the MUX-120 was less capable for the same price.

In the end, I picked the VX because I've never had a Thermalright heat sink. I've never had a Prolimatech, either, but TR is sort of famous. Just as important was the fact that I was able to confirm that I'd be able to fit the VX with a 120x25mm fan on the ASUS P8P67 with 4 sticks of Ripjaws X. I'd like to say that it was due to some impressive performance metric, but the more I looked, the more I realized that I wouldn't see much difference between the VX, Megahalems or Fenrir. So, this time I'll try Thermalright. I'll try something different next time.

In my case I will experiment. If the noiseblocker pwms work for you, I might try them. But I will probably start off with a single 800 rpm slipstream running at a steady 12v. That may be all that I need... even while benchmarking.

Sandy Bridge doesn't seem to need much in the way of cooling, but overclocking is still overclocking. People were reaching 4.5GHz with the Hyper 212, but they were using high speed fans. Since I don't have any experience with this (yet), I can't say for sure, but from what I've seen, you'll need either a fan with higher static pressure or higher CFM (or both) to get to 4.5GHz with decent temperatures.

[Fire-Flare]

check out the scythe mugen-2 review to hear spcrs take on the slipstream pwm.

I use that cooler with a second Slipstream in push-pull. Keeps my 3GHz 6-core CPU near room temperature and my laptop hard drives are louder at idle!

[figment]

Seems like the NB-Multiframe M-12ps or the Slipstream might be the safest choice if sound is your preeminent consideration. The other two Noiseblockers can slow only to 1000 rpm.

I was actually looking at the BlackSilentPro-PLPS [FrozenCPU]: 600-1500rpm +/-10%, claimed 23-58 CFM at 0.15A.

No matter how well they are designed and constructed, it is going to be hard for them to match a NB-Multiframe M-12ps at 600 rpm or a slipstream at under 500 rpm.

The BlackSilentPro fan has the same motor and bearings as the Multiframe M12-PS (notice the same rpm band), but a classic fan housing that will work with standard fan clips. I'm getting a Venomous-X without the large plastic box-clips (because its cheaper). The BlackSilentPro is also about $8 cheaper than the Multiframe.

Dual fans on such a powerful cooler will probably almost always be running at their minimum speed.

That's the plan. If I can push/pull them, then I'd be able to run them at minimum at all times except intense gaming or video encoding or large compression jobs (backups, probably).

The slipstream specs are sort of interesting. I wonder what that 0 rpm means in real life operation?

I was confused by that too. Do they really have a fan that can operate at, for example, 5% duty cycle? That would be an impressive --albeit useless-- feat.

[fumino]

The slipstream specs are sort of interesting. I wonder what that 0 rpm means in real life operation?

I was confused by that too. Do they really have a fan that can operate at, for example, 5% duty cycle? That would be an impressive --albeit useless-- feat.

05% pwm set by speedfan = ~144rpm. note that it definitely wont start at this speed, but you can get it spinning, then lower it after; i have my bios set to run the fan at full, then speedfan takes over after startup.

if youre not settled 100% on the venomous x, really consider the mugen-2. it comes with one of these excellent fans, and its still like half the cost... thats a pretty solid deal imho. throw in another fan; a pwm splitter; another pair of fan clips or some 8" zip ties; and youre set up for some serious, quiet cooling.

[quest_for_silence]

I was actually looking at the BlackSilentPro-PLPS [FrozenCPU]: 600-1500rpm +/-10%, claimed 23-58 CFM at 0.15A.

You may give a look also to the Enermax Cluster, IME probably slightly more rough at full speed than the Slipstream (subjectively), but with a far better bearing (it's also detachable for cleaning, and if you mind you may light it up).

EDIT: I also own the Kama Flex PWM (I've right now saw that you have some doubts about SA1225FDB12H-P): it's somewhat intermediate between the Slipstream and the Cluster, but its most drawback is IME the closed frame corners, a real pita for a CPU fan. Otherwise, subjectively it sounds very good and probably have one of the best bearing in the PWM field.

[SebRad]

Hi, I'm using an Arctic Cooling F12 PWM fan on my CPU cooler.
While it may not be the absolute best it is still very quiet, currently throttled down to 18% 530rpm. Needs to get to ~800rpm before become noticeable to me.
Comes with PWM sharing wiring built in and can route the speed signal from other fan(s) to other motherboard headers if required.
They have some sort of fluid bearings and a 6 year warranty and are very cheap. E.G.

Seb

[ces]

Enermax fans are sort of interesting. I have always been a bit wary of placing these fans, with such super strong magnets, near hard drives.

SPCR did a review of the one of this family of fans. One without the "bat wing" blades:

Their sound level "was low and changed very little with speed. This is markedly different from how fans usually behave; as a general rule speed and noise are strongly correlated, but the Marathon varied more based on listening angle than rotation speed. Unfortunately for the Marathon, it happened to be loudest at the angle that we typically measure from — 45° off the exhaust side" "..thanks to the hugely directional noise pattern, the best we can say is that it might be worth experimenting with."

"The fan exhibited a couple of other oddities as well. For reasons that never became apparent, the Marathon did not move as much air per rotation as many of the other fans we tested. Like the Arctic Fan 12L, the Marathon seemed to lag about 5~10% behind the airflow produced by other fans. But, while the Arctic Fan could probably attribute this to its frameless design, the Marathon doesn't have this excuse. "

"Another oddity was the way the Marathon started up. Given a sudden burst of voltage (our usual method for testing starting voltage), the fan started reliably at 6.6V. However, if the voltage was increased gradually, the fan wouldn't start until a full 12V was reached. This could pose a problem if the Marathon ever stalls when undervolted. When the fan was stopped forcibly, it had trouble restarting unless the input voltage was close to 12V."

"All in all, the Marathon (and presumably Enermax' other Enlobal fans) is a very interesting fan, but until some of its quirks are worked out, it won't stand out in the crowd as much as Enermax might like. For us, the biggest issue was the highly directional, resonant pure tone that made judging the noise character so difficult."

"...it's worth pointing out that other users have had issued with vibration and quality control."

http://www.silentpcreview.com/article739-page4.html

The "batwing" version of this family of fans exhibited very strong static pressure performance on a new fan testing site. The the dB measurements there also make them some of the loudest fans tested by this site as well.
http://atreview.net/en/casefan.html

Though, as has been pointed out, the testing methodology of this site leaves something to be desired:
viewtopic.php?p=537817#p537817
You just always need to be cautious about relying too much on information you get from the internets, even in the SPCR forums.

If you try the Enermax please post how it works out for you.

[ces]

Some Enermax user comments from newegg, some of which appear to reinforce SPCR comments:

ENERMAX UC-12EB

bought 2 of these for newest personal build and am very disappointed! fans will only run if you spin them by hand when you turn on the power

I have fiddled by moving the blade in and out slightly till it spins freely. The "fix" lasts for only a few seconds. My new 1900xt failed, too, and is in the RMA loop

I can hold a lighter 1 inch away from the fan and it barely makes the flame flicker!

The magnetic fan bearing design that this uses is really a smart idea, however it is flawed. The for this to work, both the base, and fan need to be aligned for the motor to work properly, as the fan starts to spin, the force of the air displaces the fan, moving it out of alignment, then the motor does not work, and the fan slows down. Once it slows down enough, it re-aligns, speeds up, and the process starts over again. This constant oscillation moves almost no air... (PS - I build silent pc's, so i'm aware of air flow / noise ratio, these are worthless by comparison to over silent fans available)

after about 3-6 months, the fans start buzzing, vibrating, running unsmoothly, making a loud noise in the computer housing. Tapping the fan will make it run quietly for a few minutes, before it begins again. When I got irritated enough I replaced it it with the next of the eight I bought, and had the same experience. After a year and a half, I am on fan four or five out of eight.

Was practically noiseless for the first week or so, then an extremely annoying, loud vibration set in. It could be reduced somewhat by loosing the screws attaching it to the case, but not eliminated

DOES NOT SPIN ON STARTUP! You have to manually start the blades moving like its a world war one biplane!

UC-MA12

Detachable blades for cleaning, nice feature. Push a lot of air... but most LOUD fans do... see CONs...

18db??? ARE YOU KIDDING ME? The WHOLE reason I bought these were based on all the "OH they are soooo quiet" reviews... and still push so much air. W/E... I just spent an hour swapping out the fans supplied with the Corsair H70 cooler which are loud as hell at least 35db and guess what... these are as loud... however not as shrilling loud. Still. Totally disappointed. And to boot my temps in my Prime95 torture test about about 10deg off of what I had with the Corsair fans.

Amazingly noisy at full speed. It's air noise, not bad bearings or poor construction. The 18dB rating is simply false. I am here looking for replacements, because the 3 fans in my equipment cabinet are just too distracting, even when slowed to 700 rpm. They are much noisier than the 2 120mm fans that came with my Lian Li PC-C50B HTPC case

I am using this on an air intake and something about it just doesn't stay very quiet. Easily the loudest fan in my system and the exhaust fan (thermaltake) came with the case and the CPU fan (Coolermaster) came with the H212+ cooler i bought. It's on quiet mode too...really odd

Amazing air flow! When it's running at 1500 RPM, the temperture of my computer drop down from 41 to 33!. However, the noise level supposed to be 58 dB! It's not a joke. If you are looking for a super slient case fan. This one is not your choice!. But if you set this run at 1000 RPM, it's much more slient. Still more noiser than Scythe S-FLEX.... This company claim this fans only have 18 dB. It's a joke!.

This fan makes a little bit of a funny noise that it made ever since the first time I turned it on. I think the sound is coming from the shape of the fins. If i cover a small portion of it with paper and change the shape of the air draw, the noise goes away. Goofy but if you notice that sort of thing and it bugs you, maybe look elsewhere

After two months of use, one of the fans started giving me a grinding noise, I'm still dealing with it but I think its just dust.... Great fans, quiet and worth every penny. As long as you clean the dust away regularly that is.

[figment]

You may give a look also to the Enermax Cluster, IME probably slightly more rough at full speed than the Slipstream (subjectively), but with a far better bearing (it's also detachable for cleaning, and if you mind you may light it up).

I actually own a Cluster. I got it as a freebie from Enermax for reviewing (honestly) the Modu82+ PSU right after it was released. It's a decent fan, but I'd say its easily inferior to the newer generation of Twister Bearing fans and easily a step or two louder than my Slipstreams. The bearing is really cool, but the motor seems to have a high pitched whirring/clicky noise in the background. I'm using it as a CPU fan on my Linux box. It's fine when it has to be filtered through other fans, but I wouldn't put it anywhere near an opening.

I also own the Kama Flex PWM (I've right now saw that you have some doubts about SA1225FDB12H-P): it's somewhat intermediate between the Slipstream and the Cluster, but its most drawback is IME the closed frame corners, a real pita for a CPU fan. Otherwise, subjectively it sounds very good and probably have one of the best bearing in the PWM field.

I bought one of the Kama PWMs three years ago and had the same experience. I had to buy another fan to act as my CPU fan because it had closed corners. The Kama FLEX PWM that I'm seeing now (in the US, at least) does not have closed corners: see images at NewEgg.

Hi, I'm using an Arctic Cooling F12 PWM fan on my CPU cooler.
While it may not be the absolute best it is still very quiet, currently throttled down to 18% 530rpm. Needs to get to ~800rpm before become noticeable to me.

Oddly enough, the Cluster fan I got replaced a AC F12 PWM fan. The AC was indeed pretty quiet, however, it was also pretty ineffective. I dropped temperatures on the CPU by 8C moving to the Cluster, and that was at idle. At load, the Cluster was still quieter because it didn't have to spin up nearly as fast to keep the CPU cool.

AC fans are quiet, but I wouldn't recommend them for overclocking quad-core CPUs.

[ces]

the newer generation of Twister Bearing fans

So what is your assessment of the newer generation of Twister Bearing fans in comparison to nexus or slipstream?

Does that newer generation of Twister Bearing fans include the Magna with the batwings?

Also, do you have any first hand experience with the problem of the Enermax fans having problems at less than 12 volts?

I own an unused Magna, I was wondering if it is worth unboxing and using it? Especially if I have to worry about it stalling someday without me being aware of it.

[figment]

So what is your assessment of the newer generation of Twister Bearing fans in comparison to nexus or slipstream?

Hard to say, really. I've never actually held one, so all I've got to go on are some unscientific tests and youtube videos. I'd say that it's hard to beat the nexus or slipstream for all-around versatility. From what I've heard, the twister fans only really have an edge in static pressure and lifetime. They might be able to give better CFM/dBA at full voltage in some situations, but that's a pretty narrow band of specialization.

Worth noting here: I haven't picked a case yet (Arc Midi please?!). but I expect to replace the stock fans and I'll be going with slipstreams (except for horizontal mounts).

Does that newer generation of Twister Bearing fans include the Magna with the batwings?

No. Unless I misunderstand, the generations go: First: "Everest", then "Magma" and "Cluster" (PWM). Second: "Appolish", "Appolish Vegas". The Magma and Cluster are the ones with the Batwing design, and those are the ones I got for free. The Cluster is on an AC Freezer64 and the Magma is a case intake on a Sonata (the same system).

Also, do you have any first hand experience with the problem of the Enermax fans having problems at less than 12 volts?

I think so. I have the Magma as an intake and I was able to voltage-control it via the motherboard, but I found that the performance of the fan dropped off quickly when undervolted and it either made more noise, or the reduction in turbulence noise made the motor noise more noticeable.

I own an unused Magna, I was wondering if it is worth unboxing and using it? Especially if I have to worry about it stalling someday without me being aware of it.

I was able to duplicate the stalling issue when I was playing with the fan, but even when I was undervolting it, I never had it happen in use, of course, I never dropped it below 8V. I could see how a 7V undervolt might stall, or if you were dynamically adjusting, a sudden drop of voltage might let it fall into a stall. I didn't find the fan to be loud at 12V, and it didn't have the clicky sound of the Cluster (PWM issue?), so I'd think it would be fine as a 12V or 8V fan.

[ces]

No. Unless I misunderstand, the generations go: First: "Everest", then "Magma" and "Cluster" (PWM). Second: "Appolish", "Appolish Vegas". The Magma and Cluster are the ones with the Batwing design, and those are the ones I got for free. The Cluster is on an AC Freezer64 and the Magma is a case intake on a Sonata (the same system).

1. That is interesting. It seems the "Everest" and "Cluster" (there was no "Magna") along with the Gentle Typhoons generated the most static pressure with some of the lower or lowest dB levels.

The "Appolish" has some of the very lowest sound levels of all the fans, but didn't do so well on static pressure.

2. It appears that my Magna isn't good for much. It's Nexus and sliptream... or if high static pressure is called for, or it is a horizontal installation its Gentle Typhoon. Maybe the Magna would be good if I water cooled, but that's about it. Can you save me here?

http://atreview.net/en/casefan.html

[quest_for_silence]

2. It appears that my Magna isn't good for much.

I don't think so (so I wouldn't say so), at least because there isn't only the "intake fan job" inside a case.

Perhaps it might worth to give a second look to an objectve and subjective short test made some time ago by Felger Carbon (one of the most fantastic and competent people ever seen here on SPCR: to use his nephew's words, he was "larger than life"), about the Enermax MagMa and the Slipstream M (with, indirectly, an utterly concise comparative assessment about the Nexus).

viewtopic.php?t=47568

Or what Devon Cooke himself wrote two years ago in the SPCR's ECO80-II review about the Enermax Magma:

Bad as they are, Enermax' overwrought marketing buzzwords can be forgiven because the Magma fan — with its Batwing blades and its Twister bearings — really is quiet. Exceptionally so. We really need to get hold of some individual fan samples, because this power supply is worth it just for the fan.

[quest_for_silence]

It seems the "Everest" and "Cluster" (there was no "Magna") along with the Gentle Typhoons generated the most static pressure with some of the lower or lowest dB levels.

Where are those static pressure data? (BTW, we're going to hijack this thread, apparently strictly related to PWM fans).

[quest_for_silence]

I was able to duplicate the stalling issue when I was playing with the fan, but even when I was undervolting it, I never had it happen in use, of course, I never dropped it below 8V. I could see how a 7V undervolt might stall, or if you were dynamically adjusting, a sudden drop of voltage might let it fall into a stall. I didn't find the fan to be loud at 12V, and it didn't have the clicky sound of the Cluster (PWM issue?), so I'd think it would be fine as a 12V or 8V fan.

I'm not sure to have understood you: aren't you using PWM control for that Cluster? Or these tests has to be referred to the Magma?

[figment]

2. It appears that my Magna isn't good for much. It's Nexus and sliptream... or if high static pressure is called for, or it is a horizontal installation its Gentle Typhoon. Maybe the Magna would be good if I water cooled, but that's about it. Can you save me here?

I wouldn't say that the Magma is useless, I just don't think that its really the best at any one thing. It's quiet, but not as quiet as some of the Noctuas or Slipstreams at equivalent CFM. It's got good static pressure, but not as good as the GTs or some other high pressure fans. Perhaps its strongest attribute is its rated life, but people don't often go looking for fans that will last 10 years.

However, not being the best is not the same as being useless. It's a decent fan, with some drawbacks. I know mine was a bit noisy at sub 12V, but that might have been fixed (the Magma wasn't even released to the public when I got it). At 12V, its no noisier than a lot of the fans people use, even here at SPCR.

[figment]

I was able to duplicate the stalling issue when I was playing with the fan, but even when I was undervolting it, I never had it happen in use, of course, I never dropped it below 8V. I could see how a 7V undervolt might stall, or if you were dynamically adjusting, a sudden drop of voltage might let it fall into a stall. I didn't find the fan to be loud at 12V, and it didn't have the clicky sound of the Cluster (PWM issue?), so I'd think it would be fine as a 12V or 8V fan.

I'm not sure to have understood you: aren't you using PWM control for that Cluster? Or these tests has to be referred to the Magma?

I was talking about the Magma. I wasn't able to "stall" the Cluster, but I did notice that it took a lot less force to stop (ie: pressure on the hub) to bring the fan to a stop.

[lodestar]

In March of this year Enermax introduced a PWM version of the 120mm T.B. Silence, model UCTB12P, as an entry level Twister PWM fan. This fan has a nominal rpm range of 500-1500. To me this positions it against the NB-BlackSilentPro PLPS, which is 600 to 1500. Of the two, the PLPS is probably a better bet in silence terms. So going back to what the OP was saying, it still seems to be a straight choice between the Slipstream SY1225SL12LM-P or the BlackSilentPro PLPS.

[ces]

Slipstream SY1225SL12LM-P or the BlackSilentPro PLPS

It would be pretty hard to make a mistake between those two... they both come from good families and all.