When considering a fan for heatsink, is there something more important than CFM?

[shaolin95]

So I was playing with some fans I have like the Scythe Kaze 3000 (died in a terrible accident), and old thermaltake t1225 and the newer t1225h plus the Scythe Slip stream the high speed one rated at 110 I believe or so.
Anyway, one thing I noticed is that the "fastest" not always seems to have the strongest air if you know what I mean so I guess that is where the whole case fan vs heatsink fan comes into play.
Thus, what should I look for when wanting to get a fan for a heatsink like the mugen 2?
BTW, the Kaze, as noisy as it is, must have a bogus CFM rating as numbers wise it should have been close to a Delta I have but it was a not contest CFM AND noise wise!

[Kimi]

Static pressure is very important also, especialy when you want to put a fan on a heatsink/radiator/behind a thick dust filter. You need something that has enough power to push the air through the dense fins. Usualy 38mm thick fans have better static pressure than any other 25mm thick fan at the same RPM.

CFM is important only when there's nothing to obstruct the air, like fan grills. If the fan doesn't have a good static pressure then the specified high CFM is useless.

[shaolin95]

So what is considered good and what part of the specifications show that?
I am looking for example at the Scythe Ultra Kaze 3000 and do not see much listed except CFM and Noise.

[Kimi]

Not all manufacturers declare the static pressure. It's measured in mm H2O or sometimes inch H2O and it should be somewhere above 1.5 mm H2O to perform good (for a silent 120x25mm fan; I don't know anything about any higher rpm fans or 120x38mm fans), but this really depends on your needs. Maybe you would prefer a powerfull fan rather then a silent one so you may not be happy with that static pressure and you need more, so as I said it really depends on your needs.

[shaolin95]

Got it.
I always trusted Scythe so I was very disappointed with their air "strenght" compared to some others I tried based on their claims. I still like them, just not as much. lol

[Mescalamba]

Sanyo Denki, Yate Loon (high RPM - 3000 ones), Deltas..

I´m prefering Yate Loon over everything else, cause they usually are quiet + powerfull.. And easiest to get. Deltas are fans on steroids, but incredible noise aswell. Rest I don´t know personaly.. just know they are supposed to be good.

It would be nice if Noctua produced some high RPM fans.. with their design, it could push some serious pressure.

[shaolin95]

Yeah, just read a test by benchmark reviews where the yate loon beat the scythe ultra kaze 3000 for heatsink use.
http://benchmarkreviews.com/index.ph...&limitstart=13

[zanzabar]

if u want the best then u need to get a sanace

[shaolin95]

So it is still the best for heatsinks.
I am going to wait and see how the new Noctua cooler turns out.
If it is as good as it seem, I will get that then....although I guess I can always use the san ace with that one too and remove those ugly fans. lol

[žile]

I am not sure that you want >1100rpm fan attached to your heatsink for 24/7 use?
Other than rpm and static pressure (noise and flow wise), you should take into the account the
bearings too.
Sleeve bearings are the worst and increased ambiental temperature will affect their MTBF
exponentially - higher the ambiental temperature means less MTBF.

Therefore, for example Slipstream would not be my weapon of choice for being a heatsink fan.
I would go with S-flex's S-FDB for heatsink fan because they have the best bearings,and still are
capable to push decent amount of air in high restriction environment (radiator,TRUE's fins etc.).
Second choice would be Gentle Typhoon imo, not as good as S-flex, worse bearings and large fan hub which affects
airflow are downsides, but still are capable to push decent amount of air on acceptable noise level.

If you are looking for some extreme 3-4k rpm fan,then go with delta or some other industrial grade fan for short term
benches on cold air (sounds like phun ).
But don't try to sit next to it for too long since that noise level is anywhere near acceptable.
My combination would be S-Flex on 1200rpm,probably rpms reduced further for 24/7 and delta for benches.

[demonkevy666]

thickness of a blade is unless, it's blade design, fact curved blades have more surface area, straight blades cause more turbulence and more noise. more surface area will translate to more cfm a low rpms.

turbulence " or swirling" of air isn't bad it there isn't any restriction like exit fan. it's when it's used a tightly packed fans it tends bounce back out instead of going threw like a straight flow would do.

bearings: I have no problems with sleeved fans, how ever people tend to oil them which then causes problems because they are meant to be greased not oiled. they do not over heat, or heat up anything. The bearing they're sitting on has grease needs heat to be come oil >_>

fluid dynamic & magnetic are suppose to be the quietest bearings. 2 balls have been out a while and can be found in ceramic form, they last much longer then steel ones. they're smooth but past at a certain rpm you'll notice them.

Sanace are nice for CFM and noise balance they are better then a delta, imo.

if can't find one or too pricy try some coolink fan off frozencpu they have a nice pwm one.

[spookmineer]

Originally Posted by Mescalamba

It would be nice if Noctua produced some high RPM fans.. with their design, it could push some serious pressure.

Noctuas aren't very good as heatsink fans. They perform very good as case fans but they lack the needed backpressure if you use them on a heatsink.

[fragmasterMax]

The power of 12v fans is usually marked in amps on the fan. It should be between .05 and 1.5A. to get the power (watts) you just multiply the amps times volts. so the more amps the more power, and usually the higher rpm, and cfm (two other important factors.)
But I'm assuming that where talking about 120mm fans. Size really does matter, try and get the largest one with the most amps

[shaolin95]

I am getting a San Ace and will try to couple it with a super Delta I got with a fan controller.
I am probably getting a Noctua NH-D14 so I do not want to go crazy until I got that.