• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

strange fan/air question for heatsink mount

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

Rich'[ard]

Member
Joined
Apr 28, 2008
Location
Melb, AUS
do fans pull air as well as they push, if mounted on a heatisnk?
i ask this because...here's the scenario :)

i have 1 fan on my TRUE which is mounted horizontally. i currently have a fan beneath it pushing air up through the heatsink out my 200mm fan in my antec 900.
but say if i put the fan on top of the TRUE, so it would be pulling air OUT of the heatsink. will airflow/temps be the same?

is it better to have a fan push air INTO the heatsink or have a fun suck out the hot air FROM the heatsink?

there's an easy solution to just get another fan...but just asking lol.
fans always seem like there's a lot of air being pushed through, but i can't feel it sucking any air when i put my hand on the other side.
 

baditude_df

Northern Senior
Joined
Apr 24, 2007
Technically the air coming in = the air coming out. But the air that comes out the business end is directional or aimed, whereas the intake end just gulps whatever is in front and directly around it. Pull fans do work, but not nearly as efficiently as push fans.
If you have any highspeed fans like a Denki or a Delta, put your hand directly in front of it and listen (if you haven't already). You can really hear the air whooshing through the restricted space you have created.
 
OP
Rich'[ard]

Rich'[ard]

Member
Joined
Apr 28, 2008
Location
Melb, AUS
yeah cool,
i was thinking. the air should be equal on both sides, but the air being pulled is never feels as strong as the air being pushed when i put my hand over the fan.

i plan on getting 1 Scythe Ultra Kaze and using it on my TRUE. guess the push position is better.

thanks :beer:
 

baditude_df

Northern Senior
Joined
Apr 24, 2007
Yea you just need the pressure, and not the suction.
Ultrakaze are nice from what I hear. Never used one. They would be nicer nice if they put the FDB in them instead of a sleeve though. I've used Panaflo's and Denkis on fan controllers with both the TRUE and the Megahalems and both worked very well. Larger hubs but it doesn't seem to matter, as the air is still hitting the part of the fin that gets the heat first.
Typically I do like to go with the 38mm on a AIR sink though, as they do tend to put out a little more pressure per RMP than their 25mm counterparts.
 

Bobnova

Senior Member
Joined
May 10, 2009
All pumps, including fans, are more efficient at pushing then pulling, regardless of design and working fluid. Fans take a larger hit then some things, if you're only going to run one fan push is the way to go.
Adding a pull fan does help though.
 
OP
Rich'[ard]

Rich'[ard]

Member
Joined
Apr 28, 2008
Location
Melb, AUS
yeah Baditude, i want the Ultra Kaze for the cfm and high static pressure from its 38mm thickness. can't find any Deltas or anything similar here in Melbourne.

thanks for the reply Bob. i have tones of Antec tri cool fans hanging around, and i could just slop one for a push-pull config but i'm trying to keep the dust and noise and flashy-ness at a minimum :p
push is the way to go!

:beer:
 

ehume

Member
Joined
Oct 30, 2009
You might wish to consider a push-pull arrangement. The reviews I have seen show that two fans produce better cooling than a single fan.
 

baditude_df

Northern Senior
Joined
Apr 24, 2007
You might wish to consider a push-pull arrangement. The reviews I have seen show that two fans produce better cooling than a single fan.

It's not really worth the extra money or effort in my experience.
But yes, slightly better temperatures. Slightly. You're usually looking at a degree, maybe 2.
If you'd like, you can refer to my findings in this thread. YMMV.
Or muddocktor's thread here.
 

muddocktor

Retired
Joined
Nov 1, 2001
Location
New Iberia, LA
^^^What he said!^^^

:D

If you have the extra fan and clips (or zip ties), then go for it. But unless you are trying to run some really low cfm, low rpm silent fans (like the Noctua fans) it's not worth it IMO. Both of our threads have shown similar findings, one on LGA1366 and the other on LGA775, both with quad core processors that dump a lot of heat into the heatsink.