Difference in temp with fan outside/inside?

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JEN
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Difference in temp with fan outside/inside?

Post by JEN » Thu May 08, 2003 9:45 am

Is cooling of the PSU reduced in any way by placing the fan outside instead of inside the PSU?

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Re: Difference in temp with fan outside/inside?

Post by Athlon Powers » Thu May 08, 2003 9:47 am

JEN wrote:Is cooling of the PSU reduced in any way by placing the fan outside instead of inside the PSU?
I wouldn't think so, why do you ask?

rpc180
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Post by rpc180 » Thu May 08, 2003 11:07 am

It might, but I think it depends on the setup inside your PSU. Moving the fan to the outside separates it from components that create noise. However, if you have a low speed fan (which basically means low pressure), the diffused air speed around those components may not be sufficient to spot cool them.

Is this really important? PSUs with large (read new fortron/zalman/nexus/ExoticPC) heatsinks won't really care since the diffused airflow will still be going every which way over the heatsinks themselves. However, standard cheapo PSU's with smaller sinks may depend on close sources of fans for the air pressure to cool them off.

I tried a 92mm fan outside mounted to an antec PSU. I sealed the lower hole which held another fan (air will take the shortest route and thus air that came from the bottom hole would go directly to the fan and only skim the small heatsinks) to test it and left only the vents directly across from the fan open. The PSU exhast temperatures were so high that the fan grill was hot to the touch.
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Post by pingu666 » Thu May 08, 2003 1:22 pm

ive moved it outside on my cheapy with a papst
didnt do checks, but was a lil bit quieter
fan at 7v, about 7db tho :D
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edcrane
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Post by edcrane » Fri May 09, 2003 10:30 am

pingu666 wrote:ive moved it outside on my cheapy with a papst
didnt do checks, but was a lil bit quieter
fan at 7v, about 7db tho :D
it was quieter OUTSIDE the PSU unit? my cheapo psu has a papst 12db and it's about 1/64" too wide for the psu. I have to keep one side unscrewed to prevent the blade from touching an elevated circuit board. I was considering putting it outside as well, but I don't see why it would be quieter.

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Post by Jan Kivar » Sat May 10, 2003 11:22 am

If there are some components near the fan (say less than one cm) moving the fan outside should drop the turbulence noise caused by these components. However, as rpc180 pointed out, the air pressure inside the PSU will drop a bit, especially if the joint between the fan and the PSU isn't perfect, so the fan sucks air in from the joint.

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Post by pingu666 » Sun May 11, 2003 6:48 am

yeah thats why i moved it out, small difference :)
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