Does anyone know anything about fans???? I need a good fan!

[Ilmater]

I've got to quickly pick a good fan. I don't know how much difference in case cooling it would make to have a 35CFM fan vs. a 27CFM fan. The noise ratings are even harder to judge. Just because one fan runs at 28dB(A) and another runs at 26dB(A) doesn't mean anything. We all know that.

I have to pick fans for a friend's computer tomorrow and I don't know which are best. I know that Panaflo L1A's are very quiet, but do they push enough air to run a computer at fairly good temps? Vantec Stealths?

Are sleeve bearings quieter than ball bearings or is it the other way around? I thought that sleeve bearings were quieter but didn't last quite as long. Here are the fans and ratings I've looked at so far. Please comment if you've used any of them, all are 80x80x25:

Sunon 36.5 CFM @ 2700 RPM, 30 dBA
Zalman 39 CFM @ 3000 RPM, 34 dBA - or - 28 CFM @ 1700 RPM, 20 dBA (resistor included changes it from 12V to 5.5V)
NMB 18 CFM, < 18 dBA (that's what this says)
Vantec Stealth 27 CFM @ 2050 RPM, 21 dBA
Panaflo L1A 24 CFM @ 1900 RPM, 21 dBA
Panaflo M1A 32 CFM, 28 dBA
Panaflo H1A 39.6 CFM, 32 dBA
YS Tech 48.5 CFM @ 3300, 36.9dBA

These are the best I've found. The friend used to have a cooler (that was improperly installed NOT by me) that didn't work very well, so when he played games, he had to take the side off of his computer and use a standing fan to blow air in the case. Therefore, he's used to loud fans. However, I'd like to find a good balance between noise and cooling performance. It doesn't need to be completely silent, but it would be nice if it were close. Cooling is really the most important part. I don't believe that the Panaflo L1A puts out quite enough air to have much of an effect on cooling, but maybe I'm wrong. These fans are going into an Antec Performance Plus 660 AMG case, if it makes any difference. You all know that it comes with a TruePower 330w PS. If many of these fans are quieter, then I won't have to worry about anything.

PLEASE HELP!

 

[Ilmater]

Bump

 

[Goi]

CFM ratings measure the airflow of the fan, it stands for Cubic Feet per Minute, so the more the better. However, all other things being equal, the more airflow a fan has, the louder it will be, which is where the dBa ratings come in. They measure the sound volume output in decibels. Generally, a 3dB difference is the smallest perceptible volume difference, whereas a 6-10dB increase would be generally perceived as a doubling in sound volume. However, don't trust the manufacturer's rating like the bible, it can only be used as a guide.
Sleeve bearing fans generally are quieter but don't last as long as ball bearing fans.

Generally, Panaflos and Papst fans are the quietests, and Delta/YS Techs are pretty loud. Sunon makes good quality fans but don't excel in any particular field.

 

[Ilmater]

I appreciate the response, but I already know what CFM and dBA meant. What I need to know is, does anyone know how much difference does 3 or 4 CFM make? Are Vantec Stealths really silent (I've heard not)?

 

[Goi]

As I've said, 3dB is at the threshold of your ability to tell the difference, so yes, you'll be able to tell a diff. Will the difference be large? Probably not. Another thing to note is that not all fans produce the same sort of sound. You might prefer a lower rumble that's louder to a high pitched squeal that's softer.

 

[Ilmater]

I get the dBA part. I understand that a 3dBA increase means doubling the "power" of the sound. I also understand that some fans have a whining sound (much worse than a low rumble btw) while others don't. That's why I asked the question. Since I haven't actually heard most of those fans, I can't judge the actual loudness of them. Therefore, I need people who have actually heard them to tell me how bad the sound of these fans really are. For instance, I've also heard that ThermalTake's fans aren't very true to their sound ratings. If someone knows that all of these fans are true to their dBA ratings and don't have that high whining sound, then I'll use my own judgement as to how much noise will be tolerated.

However, I am almost completely clueless about how much difference CFMs make. Is it worth 2 or 3 dBA (up to a point) to get 4 or 5 more CFM? Will it make much difference in the actual cooling of components within the case?

 

[Goi]

Alright, if you're asking for personal experiences with the fans, I can't help you there. I can only tell you about my experience with the fans I own. However, none of them appear on your list

As for your CFM question, my experience is that for case cooling, you can get away with less CFM, its less critical than for CPU cooling. As long as there's a steady flow of air within the case, you should be fine. A difference of 4-5CFM probably isn't gonna be much, unless you're talking about a difference between a 10CFM and a 15CFM fan, but case fans are normally at least 80mm, and those normally push at least 20+CFM anyway.