CPU Fan blowing in or out of heatsink? - Techist - Tech Forum

Go Back   Techist - Tech Forum > Computer Hardware > New Systems | Building and Buying
Click Here to Login
Closed Thread
 
Thread Tools Display Modes
 
Old 04-26-2006, 05:03 PM   #1 (permalink)
True Techie
 
Join Date: Aug 2005
Posts: 213
Default CPU Fan blowing in or out of heatsink?

Recently I've just put an aftermarket cooler on my rig and i noticed that the fan airflow was blowing in to the heatsink. Is this safe? It obviously came stock like this but I'm a bit concerned-does it do a better job w/ the airflow out or in?
__________________

__________________
Athlon X2 Brisbane 3600+ @ 2.91Ghz
Arctic Cooling Freezer 64 Pro
Biostar TForce 550
2GB Wintec AMPO DDR667 @ 831Mhz
Connect3D X1900GT Rev.2 580/1602
Hitachi Deskstar 80gb SATA + 80gb WD Caviar IDE
Fortron FSP Group 400W (18A/16A 12V)
http://service.futuremark.com/orb/re...=0&UID=9889664
5122 in 3DMark06
rx7i2 is offline  
Old 04-26-2006, 05:14 PM   #2 (permalink)
Sui
Ultra Techie
 
Join Date: Nov 2004
Location: Socal
Posts: 665
Default

Suck or blow, its all about heatsink design. If it came stock like that you most likly won't see anything good from turning it around.
__________________

Sui is offline  
Old 04-26-2006, 05:18 PM   #3 (permalink)
MechEng Extraordinaire
 
Join Date: Apr 2006
Posts: 1,027
Send a message via AIM to cwiz
Default

heat transfer (HT) is drastically improved when the fan is blowing onto the heatsink. HT is directly proportional to the fluid velocity (in your case air) passing over the surface of interest. if the air is being sucked from the sides of the heatsink and out of the fan, the fluid is probably in laminar or transition flow. if the air is being blown down onto the heatsink, it is probably in turbulent flow. Turbulent flow is capable of moving far (more than 2x) heat than laminar and transition flow.

the only negative that i can forsee when blowing down onto the heatsink is the mobo will be in more direct contact with the hot fluid coming off the CPU and possibly raise the temp of the area around the CPU. If your case is respirating reasonably well, however, you will not need to worry about this. (good respiration: make sure you have air INTO and OUT OF your case)
__________________
Change the world
upgrading...
PS3 -> Folding as we speak Team# 64582
cwiz is offline  
Old 04-26-2006, 05:21 PM   #4 (permalink)
MechEng Extraordinaire
 
Join Date: Apr 2006
Posts: 1,027
Send a message via AIM to cwiz
Default

It is thermodynamically impossible for your CPU to be colder than the fluid you are using to cool it with!!!!!!
__________________
Change the world
upgrading...
PS3 -> Folding as we speak Team# 64582
cwiz is offline  
Old 04-26-2006, 05:58 PM   #5 (permalink)
Sui
Ultra Techie
 
Join Date: Nov 2004
Location: Socal
Posts: 665
Default

Yes, talking about my quote? I'm quite impressed with myself for actually getting him to say that.
Sui is offline  
Old 04-26-2006, 06:01 PM   #6 (permalink)
True Techie
 
Join Date: Aug 2005
Posts: 213
Default

lol, thanks. Another question - if my intake has less of an airflow than my exhaust will it affect the temp of my case? and what about an exhaust PCI slot fan?
__________________
Athlon X2 Brisbane 3600+ @ 2.91Ghz
Arctic Cooling Freezer 64 Pro
Biostar TForce 550
2GB Wintec AMPO DDR667 @ 831Mhz
Connect3D X1900GT Rev.2 580/1602
Hitachi Deskstar 80gb SATA + 80gb WD Caviar IDE
Fortron FSP Group 400W (18A/16A 12V)
http://service.futuremark.com/orb/re...=0&UID=9889664
5122 in 3DMark06
rx7i2 is offline  
Old 04-27-2006, 01:39 PM   #7 (permalink)
Master Techie
 
RicoDirenzo's Avatar
 
Join Date: May 2005
Posts: 2,102
Default

Quote:
Originally posted by cwiz
It is thermodynamically impossible for your CPU to be colder than the fluid you are using to cool it with!!!!!!
Unless the contact surface is cooler than the air......which ain't gonna happen unless you freeze your mobo...........so you are not thinking "outside of the box"...........never use the word "impossible"................................

I do have a pancake for a hat!!!!
__________________
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.
RicoDirenzo is offline  
Old 04-27-2006, 05:02 PM   #8 (permalink)
Seg Fault'n
 
Join Date: Jul 2005
Location: The dried husk where America came from
Posts: 5,801
Default

the fan should blow onto the heatsink so there is no worry there
and also the exhaust should be a little more than the intake, this is to create a slightly lower pressure inside the case than outside
for more info, PM me
__________________


There are in order of increasing severity: lies, darn lies, statistics, and computer benchmarks. - diskinfo man page
"Get your money and let's go to court!" - Craig Mudie, MS
kmote is offline  
Old 04-27-2006, 06:36 PM   #9 (permalink)
True Techie
 
Join Date: Aug 2005
Posts: 213
Default

Ah, that makes sense. If i grab one of those vantec 90CFM fans will the air move too fast for an intake fan?
__________________

__________________
Athlon X2 Brisbane 3600+ @ 2.91Ghz
Arctic Cooling Freezer 64 Pro
Biostar TForce 550
2GB Wintec AMPO DDR667 @ 831Mhz
Connect3D X1900GT Rev.2 580/1602
Hitachi Deskstar 80gb SATA + 80gb WD Caviar IDE
Fortron FSP Group 400W (18A/16A 12V)
http://service.futuremark.com/orb/re...=0&UID=9889664
5122 in 3DMark06
rx7i2 is offline  
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 10:52 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.