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.'"

Comments

Fan monitoring in Linux

[CmdrTroll]

For anyone out there (myself included) who got the hankering to monitor their CPU fan speeds under Linux, try out wmalms, a handy dock applet that reads the I2C bus and reports fan activity. It could save your CPU.

-CT

Re:Heat Transfer Tip

[morcheeba]

Actually, you want it to blow hot air! That's the heat from the chip... if it blows cold air, then the heat isn't making it to the heatsink and you've got a problem. [automotive parallel: if your heater doesn't blow hot air, then your cooling system isn't working; same situation]

IIRC, AMD was recomending phase-change material instead of paste for just this reason. The paste works better... until it dries out. The phase-change material lasts longer. Just wondering... is it just me, or this the phase-change stuff seem like starburst candy? I removed my heatsinks and didn't want to reuse the p-c stuff, so I had to use paste. Could I have used a small slice of orange chew instead?

Also, everyone else, when he says "freezing" he doesn't mean cold (like I originally thought), but locking up. Took me a few seconds to figure that out. BAM!

Re:Didn't we already know that???

[MisterPo]

Fan that can move comparable amount of hot air but with less RPMs means a quieter machine :)

Personally my fans are the main source of noise in my home machines. I am in the process of looking for quiet case fans and will most definitely get a quieter CPU fan too.

I am quite surprised at your CPU being 5F cooler though.....thought it would be far higher. Does your case have a lot of fans in it already, or do you have a low power unit like VIA's C3??

Regards,

Po

Re:Isn't this all kind of pointless?

[Ryan_Amdmb]

While the General Fan Guide is a solid piece of technical writing on its own, you may want to read the Guide to Heat Transfer that was also posted, as the two topics inter-mingle so much, it may make more sense to you.

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.

Re:iMacs have no fan, Mac+ also silent, and Apple

[Anonymous Coward]

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

Re:Quiet cooling for GF3?

[htmlboy]

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.

not a fan recommendation, but i've found that a little bit of acoustic foam on the inside of a case does wonders to get rid of higher frequency fan noise. i put some on the inside of my case, and it's done wonders to keep the noise from my 7500 rpm cpu fan under control.

it's a pretty easy install, too. just wipe the dust off the case metal, spray on some 3M spray adhesive, and put the foam there. reassemble the case and you're done.

i got my foam at 2cooltek.com if you're interested in investigating further (store -> case supplies and coolers -> case mod supplies).

Re:Quiet cooling for GF3?

[commanderfoxtrot]

If you read the article, it describes the benefits of using 7 volts instead of 12 volts to run your fans. I have had my Duron and GeForce2 GTS both running on 7 volt fans for a long time -- the GeForce2 fan is now inaudible!

Take a look at 7volts.com for some more analysis.