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 Post subject: Computer fans suck.
PostPosted: Sat Jan 19, 2008 12:30 pm 
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Location: Arlington, MA
<rant-and-cautionary-tale-for-system-builders>
I spent a bunch of time last night trying to track down the source of the recent increase in noise from my media box.

Removed, cleaned, soft mounted, replaced, and then put back the 120mm case fan. Turns out it wasn't the problem. :?

Vacuumed, cleaned, inspected, adjusted ... the fan in my Zalman 7000 CPU cooler. Turns out it wasn't the problem. :?

Finally tracked the noise down to the stupid little fan on the chipset HSF assembly. (Why is it always the blasted chipset fan?) :(

Since replacing it just wasn't going to happen at 10PM last night, I ended up tearing it down, cleaning it lubing it, and reassembling the wretched little thing with it's tiny, tiny screws. That seems to have cut the noise down to tolerable levels, but replacing it with a nice over sized passive heat sink RSN is probably in the cards. :(

:idea: Next time I build a computer, the very first thing on my list is going to be replacing any stupid little fans on the mother board with passive coolers BEFORE putting it in the case. The goal will be to have anything with moving parts that goes into the box be replaceable in 20 minutes or less. :idea:
</rant-and-cautionary-tale-for-system-builders>


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 Post subject:
PostPosted: Sat Jan 19, 2008 2:01 pm 
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Location: Virginia, USA
Quote:
Computer fans suck


I thought that depended on their orientation, otherwise they blow. Sorry, couldn't resist.


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 Post subject:
PostPosted: Sat Jan 19, 2008 3:07 pm 
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ceenvee703 wrote:
I thought that depended on their orientation

Are you saying there are gay fans?!?

Seriously, I saw a project one time, I think someone linked to it from here, They took one of the big Thermaltake cases and mounded the guts from an "Ionic Breeze" air purifier to build a case that had some serious airflow with NO MOVING PARTS.

I'm not certain how smart blasting ionized air through your case is, but the idea is certainly intriguing.


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 Post subject:
PostPosted: Sat Jan 19, 2008 3:33 pm 
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Location: Arlington, MA
They both suck and blow.

Except when they stop altogether, which sucks and blows in an entirely different way.

So far the northbridge fan continues to suck and blow in the first way, and make a nasty 1khz noise. While that's better than the awful rattle it was making before, it still isn't pleasant.


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 Post subject:
PostPosted: Wed Jan 23, 2008 4:44 pm 
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Posts: 42
Fans are a pita and I am not a fan of them (pun intended.)

Pretty much everything in all of my computers is either passively cooled or cooled by water:
better performance, quieter and far less likely to fail. :)
(Power supplies are my exception- water cooling THEM is just too much trouble, though I have done it. Once.)

A few suggestions though, on fans:

Make sure they a ball-bearing fans
Most fans included with motherboards, heatsinks and cases stink and should be replaced, preferably when building a system in the first place.

Use of filters on intake fans (or passive intakes) and restricting any unfiltered air from entering the case will help lengthen the life of fans. It will cause some amount of temp increase in most systems though, due to more airflow resistance.

Good luck. :)


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 Post subject:
PostPosted: Wed Jan 23, 2008 7:17 pm 
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Location: Arlington, MA
rogerdugans wrote:
Make sure they a ball-bearing fans

Ball bearing fans tend to have a longer life but aren't necessarily quieter. Most of the top ranked fans at http://www.silentpcreview.com/ are actually either sleeve bearings (their reference fan from Nexus) or the newer fluid dynamic bearings from Sony. Ball bearing fans are also often noted for having a certain "chatter" or ball bearing character in their sound profile which many people find annoying.

rogerdugans wrote:
Most fans included with motherboards, heatsinks and cases stink and should be replaced, preferably when building a system in the first place.

Kind of depends on the heatsink or case, where it is possible to buy ones with good fans, but definitely true for motherboards. Thus my resolution to take care of that right up front next time.

rogerdugans wrote:
Use of filters

This is an interesting balancing act. Filters require higher pressures which generally means running the fan faster and making more noise. On the other hand they can help damp some noise exiting from the case. In especially dusty environments they can clog up quickly and need regular cleaning, the flip of that is they can keep the fans themselves from accumulating a lot of dust on their blades which can increase both turbulence and bearing noise. Since it's really hard (and often counter productive*) to completely seal up a case I tend to skip the filters.

* I've discovered over the years that really tight cases tend to suck in dust where you least want it, through the removable drive openings and ports. Having a USB port or optical drive stop working because it's clogged with felted dust is worse than having to vacuum dust bunnies out of the case every six months or so IMO.


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 Post subject:
PostPosted: Thu Jan 24, 2008 6:26 am 
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tjc wrote:
I've discovered over the years that really tight cases tend to suck in dust where you least want it, through the removable drive openings and ports.

I've never though about it, but looking back you're absolutely right.
You would need to have more intake fan airflow then exhaust fan airflow. This will create positive air pressure within the case. Air would then blow out the ports/drivebays rather than get sucked in. Just don't overdo it or the case could whistle like a teakettle. You'd still have the filter/don't filter debate on the intakes.

Judicious use of electrical tape or hot glue inside the case could seal the ports to make them airtight enough to be nearly dust proof, but anything bigger than a serial port is going to be a vent no matter what you do.

I wonder how system builders are going to deal with this when optical USB 3.0 ports become available.


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 Post subject:
PostPosted: Thu Jan 24, 2008 7:21 pm 
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Location: Arlington, MA
jmckeown2 wrote:
You would need to have more intake fan airflow then exhaust fan airflow. This will create positive air pressure within the case. Air would then blow out the ports/drivebays rather than get sucked in.

Yep, that's the classic solution for equipment used in hostile environments. Generally at the cost of regular filter maintenance and lots of fan noise.

I used to occasionally work with an avionics test rack, where you could feed simulated inputs to real avionics. The modules were all positive pressure, multi-filtered, and sounded like a stack of noisy cannister type vacuum cleaners. The noise was very loud (~120-140Db) and OSHA certified as hazardous to your health. ;-) Even with hearing protection nobody could stand to be in the room long.


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 Post subject:
PostPosted: Thu Jan 24, 2008 8:47 pm 
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I was actually thinking about clean-room design, which is a larger scale positive-pressure environment. For the computer case I was thinking only SLIGHTLY higher pressure -- just enough to keep the ports from sucking air. Not enough to make them whistle like a tea kettle. :lol: :lol:

I've also thought about computer room cooling where they put a Leibert unit blowing into the crawlspace under the tiles, The floor is vented under the racks which blows refrigerated air directly into the racks. My Idea is to scale that down. I have a cabinet that my mythbox is in, it has a glass door, but is open in the back, there's a closed storage cabinet under the shelf the mythbox is on. I've mused about the possibility of putting a blower in the bottom cabinet to suck air in, and blow it into the mythbox. I figure I can use a pretty powerful fan, and soundproof the cabinet to act as a muffler. I'm thinking I could make the PC case fanless at that point depending on my ductwork, maybe just a CPU fan. Of course, I then get lazy and think it would be MUCH easier to put the mythbox in the basement, and get a small formfactor PC, or even a used laptop to be my main frontend.


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 Post subject:
PostPosted: Thu Jan 31, 2008 4:37 pm 
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tjc wrote:
Ball bearing fans tend to have a longer life but aren't necessarily quieter. Most of the top ranked fans at http://www.silentpcreview.com/ are actually either sleeve bearings (their reference fan from Nexus) or the newer fluid dynamic bearings from Sony. Ball bearing fans are also often noted for having a certain "chatter" or ball bearing character in their sound profile which many people find annoying.


I agree wholeheartedly with that statement.
The only reason I always suggest bb fans is that they are proven to last, and while noise is an issue to me, longevity is more of one...
And I have seen far more issues with dead fans killing something or causing stability problems than almost anything else.

Fluid bearing fans are great, but I have concerns about the relative newness of the technology in the industry. ;)


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 Post subject:
PostPosted: Thu Jan 31, 2008 6:27 pm 
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Posts: 321
Location: Minneapolis, Minnesota, USA
rogerdugans wrote:
tjc wrote:
Ball bearing fans tend to have a longer life but aren't
necessarily quieter. Most of the top ranked fans at
http://www.silentpcreview.com/ are actually either sleeve
bearings (their reference fan from Nexus) or the newer fluid
dynamic bearings from Sony. Ball bearing fans are also often
noted for having a certain "chatter" or ball bearing character
in their sound profile which many people find annoying.


I agree wholeheartedly with that statement.


Same here.

I just installed a Zalman something-or-other on my new AM2 box,
and it's supposed to be a quiet fan. Well, I guess they're
right: the fan is quiet. What Zalman doesn't tell you is that
the motor that's spinning the fan _isn't_. If they're going to
put a ball-bearing motor in a "quiet" fan, they really ought to
spend a little extra for the ball-bearings that are round...

Hopefully it'll be a little less annoying once the case is
closed up, but if not, I'm going to have to replace that fan
with a fluid bearing one. :/

_________________
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 Post subject:
PostPosted: Thu Jan 31, 2008 7:26 pm 
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Location: Arlington, MA
Yeah, sadly the Zalman fans aren't the quietest in the world. The good news is that their fans are pretty reliable, and the heatsinks themselves are good enough that you can generally run the fan at its min speed and not overheat. Add the fact that mine is located right next to a 3 speed 120mm exhaust fan, and if my Zalman fan ever did die, I could run in emergency mode for quite a while just by switching the case fan to max.

For the rest, I don't have a huge amount of heartburn with replacing fans once in a while, if it's easy. I try to keep a couple spare 80mm and 120mm fans around so that it's not a crisis when the hardware monitoring starts crying for help or a fan starts squealing. The key is getting rid of all the fans that aren't easy to replace before they cause a problem. ;-)

Although it hasn't been a problem yet, I should probably add something to my resolution above about never using a CPU cooler with a fan that's hard to replace. ;-)


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 Post subject:
PostPosted: Thu Jan 31, 2008 10:09 pm 
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Posts: 321
Location: Minneapolis, Minnesota, USA
tjc wrote:
Yeah, sadly the Zalman fans aren't the quietest in the world.
The good news is that their fans are pretty reliable,

That's the good thing about decent ball bearing fans.
Quote:
and the heatsinks themselves are good enough that you can
generally run the fan at its min speed and not overheat.


In this case it's the 8700NT which is billed as "Ultra Quiet".
It has a PWM fan that's controlled by the motherboard as a
function of CPU temp (AMD's "cool and quiet" scheme), so it'll
only run as fast as it needs to. I can't believe I bought a
blue-LED lighted translucent fan. :/ They don't make that model
in plain black. If it gets too annoying (the noise or the
lighting), I can always replace it with a plain black fluid
bearing fan.

_________________
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 Post subject:
PostPosted: Mon Mar 31, 2008 3:51 pm 
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I made a little discovery yesterday that made me resurrect this thread. I was monkeying around inside my KM box. I was gaving it a good dusting with some compressed air. Not only did my chipset fan NOT make the satisfying "wrrrr-rrr-rrr-rr" sound when I hit it with the air; the blades didn't even move!!! I poked at it with my finger, and it was REALLY stiff. I finally powered up the box and, (you can see where this is going) NO MOTION AT ALL.

The only thing more annoying than a noisy fan is a dead fan. At least noisy fans have the courtesy to tell you they're effed. Here's the scary part. according to RRD, the fan hasn't spun for as long as I have records. (last Sept.)

Well, if the thing didn't fry after 6 (or more) months with no fan I figure I'm good with a $7 fanless heatsink. It has to do better than the busted chipfan.


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 Post subject:
PostPosted: Mon Mar 31, 2008 6:05 pm 
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Location: Arlington, MA
jmckeown2 wrote:
The only thing more annoying than a noisy fan is a dead fan.

Yeah, that's the other kind of sucking an blowing mentioned above. ;-)
jmckeown2 wrote:
Well, if the thing didn't fry after 6 (or more) months with no fan I figure I'm good with a $7 fanless heatsink. It has to do better than the busted chipfan.

Given any kind of decent airflow in the case the passive Zalman Northbridge coolers or something like that is plenty. Especially the monster ZM-NBF47 which can end up making your chipset run cooler without a fan than it did with. The only potential problem is clearance for nearby cards.


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