Ducting questions

Hi, I have some questions regarding ducting and CPU cooling in general.

1. Does the fan pull air away from the heatsink, or blow air toward it?
2. Does ducting create a tunnel that covers the fan and the heatsink?
3. Are some heatsinks (such as the SLK-800A) too big to use with ducting?

Thanks!

1: depends on ur fan, generally they blow onto the HS.
2: dont think i understand
3: dont know, havent got it.

though u can always use a "medium duct" as i call it just something that goes halfway to where u want it to go... like a vacuum cleaner

Jognt said:

1: depends on ur fan, generally they blow onto the HS.
2: dont think i understand.

Click to expand...

What I'm trying to ask is, where does a duct go? Does it lead from the fan to the CPU, therein covering the heatsink, or does it lead from the fan toward a blowhole?

aha, afaik, the standard ducts pulled in cool air, towards the fan, and the fan then blew the cool air onto the heatsink = cool cooling air, and no warm air being recycled...

i dont believe they covered the entire HS..

okay, I see. So it leads off to a place where cool air is, and the fan spits it at your heatsink. thanks!

1: In almost all cases, the fan blows into the HS.
2: Ducts go from the side panel (in general) to the fan. Some say that the duct should touch the fan and be sealed so that it only pulls in cool air; others say there should be a small space between the duct and the fan. Under no circumstances should the duct cover the heatsink.
3: Since ducting is a custom job, any heatsink will work with it as long as the fan is a standard axial type. Squirrel cage blowers are a bit trickier to duct to. And since the duct doesn't touch or cover the heatsink, size is not a consideration. Often the mouth of the duct is smaller in diameter than the heatsink.