TRUE 120 fan

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apsoul

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I'm going to need a fan or 2 for my HS by the time i get my system up and going. I have the TRUE 120 copper and I have read that due to how close the fins are on the HS I need a fan that creates high air pressure, or something along those lines. I tried looking up different fans, but some don't say pressure, just cfm, rpm, and db. Any suggestions? I'm going to take a guess and say the silverstone fans that slay is using on his TRUE would probably be a good bet, but I'm can't find his worklog showing exactly which fans he used.

It's not a priority, but if there are any red led fans that would provide ample air pressure/cfm I would prefer that. and If i could get a high pressure/cfm fan that doesn't sound like a tornado i would be pleased, but as I said not a priority. function > form
 
I've seen a few posts with users talking about fan pressure and then saying it's more important than cfm. These users have read something they don't understand but they want to sound smart.

Pressure equals Force divided by Area

Force = Mass x Velocity

Area = The size of an object or in our case the size of the fan or 120mm x 25 mm or 120mm x 38mm.

So with this info lets look at what we've got to work with, Force and Area.

Force = Mass x Velocity, and the Mass of air is determined by it's density. The only way were going to increase the Density of air (in a home environment) is by temperature or altitude. Cold air is denser than Hot air. Our fan cannot control the Mass or Density of air. So this variable has no bearing on our selection of a fan. Velocity, our fan can control the Velocity of the air. The Velocity of a fan is expressed in cfm or Cubic Feet per Minute, the key words are "per minute" which is defining a speed or Velocity just like Miles or Kilometers "per hour".

Area, we can also control this to an extent, we can buy a larger fan. A 120mm x 38mm fan has a larger Area than a 120mm x 25mm fan.

Conclusion
CFM and Area are the only values we can control when looking for a fan with maximum airflow in mind. If you have (2) equal sized fans with the same CFM rating and one is listed as having a higher Pressure then someone is a liar or they performed the testing in an artificial environment to increase the normal air density.

With all of that said I'm using these with my True Copper.
SilverStone FM123 120x120x25mm w/ Fan Controller - (FM123) - FrozenCPU.com

I'm using these fans with a Standard True on my Office Workstation.
Cooler Master 120x25mm Dual Ball Silent Fan - Blue LED (Y720DCD-25T1-GP) - 110.0CFM - FrozenCPU.com

If I was going to buy a Red LED Fan I would probably try these.
Newegg.com - COOLER MASTER R4-L2R-20CR-GP 120mm Red LED Case Fan - Case Fans
 
@OP: Are you referring to Static Pressure? If so then yes, in some cases yes static pressure is more important (typically in watercooling with high FPI rads) but I would say in most cases CFM is just as important. The static pressure rating of a fan just states how much resistance the fan can handle while still holding it's rated air flow. However, static pressure isn't TOO important in air cooling, as ordinary air heatsinks aren't that restrictive to air flow.

For example, if a fan had a very high CFM rating (open air CFM, without a heatsink/radiator in front) but very low static pressure, as soon as you put that fan in front of anything moderately restrictive (heatsink/rad/fan filter) the fan's CFM will drop significantly, whereas if you had a fan with a higher static pressure rating it would be able to keep it rated CFM through more restrictive objects.

As for what fans to get, after lurking several other forums I have seen this consensus:

Best Quality:
Scythe Gentle Typhoon 1850
http://www.sidewindercomputers.com/scge120mmsic2.html

Best Bang for Buck:
Yate Loon L/M/H
http://www.jab-tech.com/YATE-LOON-120mm-Case-Fan-D12SL-12-pr-3009.html (Low)
 
Static - Something that is not part of any perceived universe phenomena; having no motion; no particle; no wavelength.

Key Words - having no motion

Every single molecule has a static pressure and it's a constant value. It's the amount of pressure that a molecule excerts while not in motion.
Edit: Every air molecule has the same static pressure, every water molecule has the same static pressure. But a single air molecule has a different static pressure than a water molecule.

If you take a single 100cfm fan and fill a container for 1 minute and seal it tight it should have 100 cubic feet of air. If you take an identical container and a different 100cfm fan from any company and fill a container for 1 minute you will still have 100 cubic feet of air and they will both have the same Static Pressure as both containers, in a perfect world, will contain the same number of molecules. The only way to change this is to change the Mass, Velocity or Area.
 
OK so maybe what I think "static pressure" means is wrong, along with pretty much every other person I have talked to about it.

My point is, two fans that are rated for the same CFM, lets say 40 CFM (manufacturers measure this in open air, no heatsink, filter, or rad to resist airflow), will NOT always perform the same when placed in a situation where there is a lot of air resistance. This depends on the power/quality of the fan's motor.

So while what you said is correct, the static pressure rating on fans refers to (or it is SUPPOSED to refer to) how well the fan can push air through restrictive objects such as heatsinks.

At least I think so, I could be wrong. :D
 
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