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General Fan Performance Guide
Lars Olsen writes: "As a complementary article to his comprehensive General Heat Transfer Guide , Dave Smith has written another great article for Amdmb.com called General Fan Performance Guide. This is an indepth guide to the performance of the fans we have in our PC's. Here's a quote: 'The specific purpose of this guide is to take the science associated with fans and translate it into a meaningful document that will allow the reader to understand how fans work and how they apply to computers. It provides a brief summary of DC power and drives. It finishes with an introduction to the concepts of sound generation and measurement.'"
Change your thermal paste every now and then! Why do i say this? A K6 200 at work was blowing hot air...and freezing...The paste was hard as rock. I scraped it off and put new paste on. It blows cool air now, and runs better. BAM!
Life is like pants... fit in or you don't fit in.
-CT
COOLING FAN NOISE - SLEEVE BEARING VS. BALL BEARING.
Another fan page.
*rimshot*
"Trademarks are the heraldry of the new feudalism."
I have to agree that this was an excelent article.
But the gist of the article was essentialy what everybody knows... Move more air with less blades and less RPM and you have a better fan.
I do not mean to down play all the valuable equations and (the very handy) conversion tables, but didn't this article say what we already knew just in an engineers terms?
iMacs have no noisy fan, Mac+ also silent and fanless, and Apple II was fanless, and apple II GS and the NeXT had a eight foot set of cables to hide a cube 10 FEET from your ears.
Fan noise is obnoxious. good designs use cold cpu chips like powerpcs.
Apple exists in part because its machines run cool and sometimes run fanless and have many enthusiasts of utterly quiet workspaces.
SILENCE IS GOLDEN.
when you live in Quebec?
Just put the computer in a garbage bag and throw it in the snow. Cheaper than any cooling setup. Need extra long cables though, and you may need to relocate while the show plow passes.
Another alternative is using a shop-vac, which can be switched in blower mode. You can put the device in the garage, and using a few dozen feet of plastic tubing, you can route that cool air right to your CPU. Lots of cubic feet of fresh air per minute. A bit noisy, but, listen to this folks, it doubles as a vacuum cleaner! How cool (no pun intended) is this?
Think different!
J.
--- Worst tagline ever.
I didn't know a lot of that stuff, and I'll be damned if I still don't. Suffice it to say I won't be overclocking my cpu.
I'm not sure it's actually funny, but it should earn me idiocy points.
While reading the article I stuck my hand inside my case to get a feel for the air flow, and managed to nick the tip of my finger against the heat sink fan. Ouch. No apparent damage to my finger or the fan, but sure did make me jump.
For those who are wondering why I had an open case, I've been replacing a partially failed hard drive (IBM Deskstar at that, lasted 14 months).
Yes, some of the information may be more technical than needed for everyday computer enthusiasts, but that doesn't mean others aren't curious or they can't find a use for the information and theory presented in both articles.
Ryan Shrout
http://www.amdmb.com/
At work I've got a GeForce3... does anyone know of a good fan (read: the card won't melt away) that's quiet? The high pitched noise coming from the original fan is driving me nuts.
Your fireplace doesn't have a fan in the chimney to remove smoke either, but you don't often see people choking and running from their homes when they light a fire in one - unless they forget to open the flue or it gets blocked!
Hot air rises. Cooler air will take its place. A properly constructed flue takes advantage of this fact and creates a highly effective air flow without needing mechanical devices, such as fans. This is how the iMac and the Cube work. They are engineered so that the heat from the processor is channeled in such a way to create the airflow needed to cool the processor.
This "flue-effect" is combined with the design of the PowerPC processors. They are low-power consumption by nature and often use approximately 1/2 the power consumption of an equivalent mHz Pentium processor. Add to this the fact that they do run a much lower clock speed (clock speed has a lot to do with heat generation) than an equivalent computing power Pentium processor and you can see why they can run fanless.
- Graff
Just a thought about quiet PCs. If the weight of a box is not too much of a problem, then lining the case with a car audio sound deadening may be an option.
:)
For example example Dynamat (http://www.dynamat.com/), has a range of sheets that are normally used to line car panels. These not only adsorb sound but heat also. So why not??
That way you can have as many fans as you want in a system and barely hear them
Regards,
Po
The acustic properties of this must be considered.
If you close the thing up completely then
the heat won't escape as the sound deadening
will most likely also prevent heat from escaping.
Ideally one would have a system with air flow to a colder outside source and the whole thing
closed up.
One must consider what frequencies and by how much
one wants to deaden the sound. Padding the inside
of the case seems like a fire hazzard to me.
I would pad the OUTSIDE of the case if that is
what you want to do.
Remember, the padding might touch power components
and thus be exposed to very high temps and ignite.
Nice for insurance money if that is what you want.
I would rather have my house not burn down.
It isn't just lower sound that you worry about
but also safety and thermal control. Thermal control is why the fan is there in the first place.
Remember, if the outside air is hot then the
cooling effect of the fan will be incorrect.
For extreame cooling with very little sound (no
sound) use copper pipping and a full nitrogen tank. Make a coil or laberinth base with the copper pipe (a flat snake all bunched up)
Have your tank out of the room. Have the pipe come through the room. It will be a platform which the computer is mounted over (but not on as
that would be too cold.)
Open the nitrogen valve. The nitrogen will flow through the pipe and create incredibly cold temperatures. Ice will form around the pipe (which is really pretty cool). This quite system is expensive and unconventional. Make sure the nitrogen vents outside. This system has been
in use for years in labs where liquid nitrogen is 'free' in that one just needs to refill one's own tank. If you have to pay for the nitrogen then that's a bummer. But you gotta pay or the whole damn econmy grinds to a stinking halt.
So now you know the quitest way to cool something. There will be sound at the tank and at the release at the end of the pipe, so put those outside the room.
PS: just so you know that there are other uses for this, you can rap the copper pipe (1/4 or 1/2 inch in this case) around a keg and then outgas the nitrogen. That'll keep your brew chilly! Hey, and for you folks making music, you can put the CPU right next to the keg. . . (which will be frosted into a spirl of ice).
We did this in our lab for our summer party.
Gotta love that nitrogen tank.
Drink up, boys. Less talk and more heavy drinking.
I read with interest the article on system cooling fans.
:-) are actually quite useful, exhausting air out of the lower part of the system case. Expansion slot fans work especially well installed close to today's high-end AGP graphics cards, since newer cards using nVidia's GeForce3 and ATI's Radeon chipsets generate considerable amounts of heat even with small cooling fans installed on the graphics card itself.
I really think the type of cooling you need really depends on the architecture of the entire system case itself. For one thing, if you want lots of hot air being pulled out of the system case through the power supply, get something akin to the Enermax units, which sport two fans on the power supply itself.
Also, those little expansion slot exhaust fans--despite what some people think about them,
Raymond in Mountain View, CA
What I want to know, is how long these cheap little fans are going to last! This is really the most important issue in my mind.
I have no scientifically controlled empirical data set, but my random personal experience with many types of fans is that few of them perform as spec'd for very long.
Lots of engineering seems to be going into heat sinks, but without reliable fans what good is the best heat sink?
The latest fan I'm about to test is a Sunon GM1206PTBX-A "Green" 60mm. If this one develops problems I'm planning on trying a fan from Sanyo Denki. At this point though, after talking to many fan distributors, I starting to think reliable fans don't exist.
One thing that has been bothering me for some time is the amount of energy spent fighting convection in a standard PC case. Just look how often your primary exaust is a power supply fan--where the intake is about 2/3 of the way up in the case. Any air above the intake fan (HOT air) has to be drawn back down into the exaust fan or stagnate. I suspect that in most cases that hot air just stagnates (right up where you CD burner, DVD and possibly even hard drives sit).
Sorry for not including a small ascii art diagram that would have made the entire layout very obvious, but the lameness filter wouldn't even let a very dumbed down version of it through. Instead I'll try to spell it out here: (Ironically this is much lamer than just including a simple ASCII art diagram).
The case has the power supply mounted in the normal location, however it is mounted such that the power cord connecter is on the top and the intake vents point downward. In front of the power supply (lining the top of the case) are the drive bays. The top of the case is an open mesh to allow air to escape easily. CD-ROM trays will open upwards (like the Apple Cube) and the floppies will drop in from the top. Each drive will have at least half an inch of space on either side of it to allow air to flow around it. The case will have three (possibly more or less) fans mounted in the bottom blowing upwards. The bottom of the case will be on raised legs that allow air to be pulled in from underneath the case. The motherboard will be mounted normally (since case manufacturers can't really do anything about it). Ideally though you would find some way to mount the PCI and AGP cards vertically.
The rest of this post is an attempt to explain why I think this will work, and an attempt to avoid the lame lameness filter (why can't people who have good records, with say 35 or 40+ karma, get around the lameness filter?).
Anyway, my primary intent with this case design is it reduce the turbulance in the case and to use the natural tendancy for heat to rise in my favor. The input fans at the bottom of the case should keep the entire case at a slightly positive pressure. One thing you must do with this case is sit it a couple of inches off of the ground espeically if the "ground" here is shag carpeting. The drives should not be as close together as they are in a standard PC case, and they should allow air to flow freely between them. In these days of 10k and 15k RPM drives cooling your HDs is perhaps one of the most often overlooked aspects if case design. The only big problem I have with this case is the PCI slots. PCI slots are generally too close together for my liking and they are almost invariably mounted horizontally, guarenteeing that any hot card will create a hot spot on the card above it. Unfortunatly there is little a case manufacturer can do about this so I'm leaving it as a caveat. Having the power supply mounted vertically will mean that the power cord will attach to the top of your computer. I recommend either a specialy modified power supply or mounting the power supply horizontally (with the intake repositioned to the bottom of the power supply) and lengthing the case somewhat or simply leaving the power cords on the top of the case. A crafty case manufacturer might even create a little box for the ends of the power cords on the top of the case that will conceal them from general view. If you need more 3 1/2 bays, you can run them down the front of the case (in front of the motherboard) vertically. The final caveat with this configuration is that your users must remember to never stick objects on the top of this case (especially things that can spill, like coffee cups). I recommend making the top rounded or triangular or some other shape unsuited for sitting things on (but remember to leave access for things like CD-ROMs and floppy drives!).
A similar construction (albiet with more specialized hardware) to this was already used for that Apple Cube (and look how good the cooling was on that, no fan needed!) but it seems like PC manufacturuers still havn't got it. Look at practially any professional server and you'll see similar concepts in play (I'm definatly not claiming I invented any of this) almost exclusivly. Nothing here is new in the slightest and yet nearly every PC case manufacturer insists on the same general layout and same general poor quality construction. Sometimes it feels like the only thing cases are manufactured for is low cost, and all other considerations are secondary. It is this attitude of cutting every corner possible that leads to the air circulation nightmare we have in almost all modern cases. I also believe that high heat lowers the life of PC components, be it through shrinking and expanding or just plain mild constant overheating. This goes double for devices like hard drives which have actual mechanical components and thin layers of oil to worry about.
I read the internet for the articles.
Maybe not.
I see even classic Slashdot is now pretty much unusable on dial up anymore.