sucking funnel instead of a blowing 6cm fan?

[fetuchin]

ok, apparently blowing air throug funnel reduces noise but temperature increases a bit due to turbulence and those things, but if you put a say 8cm. 56cfm fan (some of thme don't surpass 31db) sucking air from the hs, turbulence would not be more that that produced by a similar-cfm6 cm fan, would it?, and if so, wouldn't it be a great idea using one of those 80 cfm monsters to do so? it would add the extra advantage that such funnel could be long enough as to situate exhaust directly out of the case avoiding heat to be thrown inside.
is it feasible? and, if not, why?

 

[whitelight]

well, some people have done what you suggested. they added an exhaust vent right about the cpu and built a duct to channel all the hot air out. but i'd recommend blowing air into your heatsink because you'll be blowing cool air into that system while displacing the hot air in there. tests have shown that blowing air into the heatsink cools it by a few more degrees than sucking air.

 

[Electric Amish]

I don't know where you've seen that whitelight.

Everything I've done/heard shows that sucking air through a HS cools better than blowing. This is especially true if you imediately vent the air that has just passed through the HS. It will keep the entire box cooler as well.

amish

 

[StrangeRanger]

<< tests have shown that blowing air into the heatsink cools it by a few more degrees than sucking air. >>


Huh?! please provide data. everything i've tried and read points the other way. by drawing air out of the heat sink you are better off. besides, that is the nature of a heat sink. long before they were used for cpus, heat sinks were (and still are) used in many applications to &quot;channel&quot;, if you will, heat away from the source. that is the whole reason a heat sink is thicker, more dense on one end than the other. the thermal energy, heat, flows from one end (thicker) to the other (thinner) end because the thin end dissapates (sp?) the heat much quicker. just like how cold and warm air currents flow.
The ideal setup would be a little funnel, or tube exiting the heated air right off the heat sink out the arse end of your case.
j

 

[Salvador]

FYI.. FWIW.. I just visited a friend that has a Dell P3 Dimensions 4100 and it has a funnel on the cpu and blows the air out the back of the case. I was surprised to see this on a stock machine. We cracked the case because he was complaining about fan noise. I didn't even want to touch his setup, especially since he has the 3 year on site service contract with Dell. I don't want to be voiding any warrantee's for him because I'm not sure why his system is set up this way.

Anyway..

Sal