cpu ducting

[Elektro Slime]

hey guys i saw this case for my lga 775 setup which has this duct over the cpu with a fan on one end sucking in air over the HSF, how effective is this method of cooling? also will i get lower temps with this type of duct cooling or regular ole cooling fans inside the case? thanx

 

[ShepsCrook]

It really depends. Ducting works in some cases. Crucial items that might effect your cooling are obviously the fans used, heatsink used, and the thermal paste. It's a lot of tweaking and adjustments to get a duct to work right. But yes, from what I've seem from people either building their own or buying pre-made ducts, they work. But it's nothing drastic.

 

[Elektro Slime]

thanx for replying ShepsCrook , but do you think ill be able to get lower temps with ducting.
Another thing, what happens to the heat being discipated from the HSF isnt the duct going to hamper the rate of removal oh heat from the HSF?

 

[ming]

I think it depends which kind of ducting you're talking about. The most common one is where there is a short lengthed plastic duct connected on to the heatsink and fan on the other end. This spreads the cool air evenly over the Heat sink which is more effective than just the HSF on its own.

The other type I've seen once is where the duct is connected to the (exhaust) fan which is actually fitted in reverse so that it blows air into the case rather than blowing it out. Some may have 120mm fans fitted which obviously provides better air flow.

What you may or may not have noticed is that a fan on it's own will blow air at almost a 180 degrees angle (in other words it spreads outwards rather than being concentrated in the centre). And this is where the duct actually helps.

 

[Sazar]

ducting for processors such as the prescott's is almost compulsory to keep ambient temp down for the rest of the items in the case...

it will generally result in a lower ambient case temp for you anyways but more so in the case of the prescott's simply due to ridiculous amount of heat generated v/s other processors in both intels and amd's family..

cpu temps will likely drop more due to lowered ambient case temp (which is where the fans generally pull the air from)

 

[albybum]

ducting that just raises the fan up from the heatsync can actually make a huge difference. When your fan is directly mounted to the heatsync there is an area of inefficiency. The center of your fan does not generate airflow when it turns and that generally is the middle of the heatsync, where heat tends to concentrate.

By raising the fan, you are allowing more uniform airflow over the heatsync.

And ducting can also lower temperatures if you are using it to pull air from outside of your case and supplying it directly over your heatsync.

If you wanted to get real fancy you could have an external air cooling system and have that pumped into your case via ducting.

 

[Sazar]

ducting that just raises the fan up from the heatsync can actually make a huge difference. When your fan is directly mounted to the heatsync there is an area of inefficiency. The center of your fan does not generate airflow when it turns and that generally is the middle of the heatsync, where heat tends to concentrate.

By raising the fan, you are allowing more uniform airflow over the heatsync.

And ducting can also lower temperatures if you are using it to pull air from outside of your case and supplying it directly over your heatsync.

yep... pretty much

If you wanted to get real fancy you could have an external air cooling system and have that pumped into your case via ducting.

this poses its own issues vis-a-vis possible condensation due to thermal differences...

if used properly and with sufficient thought given to precautions it can indeed lower temps...

 

[Elektro Slime]

thAnx for replying guys! great info too!

 

[ShepsCrook]

As you can see, most people don't comment on the ductings ability to cool and how well it would do. The main reason is that A: It's not all that popular. B: There's a lot of variables that can be influenced when working with ducting. C: Depending on how you do it, it can be minor if any improvements, or even give you a large difference.

I think most people will agree. It's almost trial and error circumstances.

 

[Elektro Slime]

well the case im lookin into got a pre built duct although im not sure wether a fan is included on the side of the case to blow air into the duct.

 

[onimkron]

Sort of off-topic, but I had a look at my friend's new Dell the other day, and it had some sort of ducting mod over the processor (never actually seen such a thing in real life before). Without taking the duct off, it seemed to have a 120mm fan drawing the heat out to the back of the case. Pretty neat, everything was very quiet, and the temps dont seem to rise that much.

 

[Steevo]

http://www.newegg.com/app/ViewProductDesc.asp?description=11-156-147&depa=1

I'm happy with my case, it's not silent, but very close. The CPU fan makes way more noise than anything else. The only thing I did extra was to flip the louvered vent so that it blew the hot exhaust air up instead of back down into the rear vent. It dropped my GPU running temp about 7 deg.