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

Fan on the heatsink? Blow or Suck?

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

rizge

Member
Joined
Jul 3, 2002
Location
Cairo, Egypt
All the retail fans will blow by default but i have seen a review (don't remember for what) that showed that with some Fans Sucking Hot Water of the Heatsink is better than blowing air into it
Also
I am planning to 4X80mm Fans on my heatsink
All Blowing IN
Shall i put 2 blowing and 2 Sucking?
 

roYal

Member
Joined
Jun 17, 2002
Location
Chicago, IL
no, don't put 2 blowing and 2 sucking. That defeats the whole purpose considering the fans will be working against eachother. The best way is to trial and error. I have a alpha 8942 and they said it's better to suck, but i found it's better to blow. Also, if you're using more then 1 fan, the fans could get damaged cause of the air flow onto another fans fins. Keep this in mind.

Also, the majority of hsf work better blowing.
 

Namagomi

Disabled
Joined
Mar 20, 2001
Location
Dallas, Texas and Tulsa, Oklahoma
my 8045 is all about the sucking. It decreases CPU temps like 1 or 2C depending on ambient, and it also decreases board temps 4C, because there isn't 80CFM of hot air being blow directly accross my 2200(BTU)+ and then onto the board.
 

flixotide

Member
Joined
Oct 29, 2002
Location
Denmark
The MIST silent twin setup I use is actually a combination of the two principles..

Observe the construction: Piccies

Now.. this construc creates a problem, hot air being pushed against a joint surface, and upwards towards the case side. In order for the entire sink to keep cool, I have to remove this very fast. Usual airflow from front to back isn't good enough. So I have constructed a duct with a sunon 35 cfm fan to suck out the air from right off the top of the heat, thus creating an extremely well working system....

Without the duct, the heat sink would hit 50 c's, and the core diode around 70... with the duct principle, the sink goes 35, the core diode between 50-55.. What a difference.
Cheers, Flixotide
 

Ugmore Baggage

Member
Joined
Feb 12, 2002
Cool air is betterer.

Air floating over the mobo is warmerer so use the fan to blow air downer into the heatsink from the coolerer case air (or even betterer -- a ducter)
 

Namagomi

Disabled
Joined
Mar 20, 2001
Location
Dallas, Texas and Tulsa, Oklahoma
ok. excessive bumpage.
try it with the fan both ways. whatever is cooler for you is the way you should keep it =P
overclocking isn't an exact science. what works for me won't always work for you. don't expect any sage advice that will solve world hunger from this board. most of us (including me) are just talking out of our *** most of the time, your best bet is to do some screwdriver work and test it out yourself.
 

nut581

Member
Joined
May 29, 2001
Location
Columbus, OH
if you have good positive case airflow (good = case temp w/ side panel closed is lower than case temp w/ opened side panel), you might want to consider sucking :)

I found a review earlier
Review
shows that positioning high CFM fan placed on a fan adapter to suck yield lower CPU temp than same fan put to blow.

While you're at it, put on a duct on your HSF, it might get even lower temp since all warm air is blown to outside the case.
 

Pfieffdog

Registered
Joined
Oct 17, 2002
nut581 said:
if you have good positive case airflow (good = case temp w/ side panel closed is lower than case temp w/ opened side panel), you might want to consider sucking :)

I found a review earlier
Review
shows that positioning high CFM fan placed on a fan adapter to suck yield lower CPU temp than same fan put to blow.

While you're at it, put on a duct on your HSF, it might get even lower temp since all warm air is blown to outside the case.

Thanks
 

UnseenMenace

UnseenModerator
Joined
Apr 23, 2001
I personally consider the suck or blow discussion generally always seems to forget one thing and that is the requirements of the heatsink.. Some produce better results having air blown against them and other prefer the latter.. its effectively a case of suck it and see. Whats good for one heatsink may not be so for another
 

palee72

Member
Joined
Sep 10, 2002
Location
Pittsburgh, PA
rizge said:
All the retail fans will blow by default but i have seen a review (don't remember for what) that showed that with some Fans Sucking Hot Water of the Heatsink is better than blowing air into it
Also
I am planning to 4X80mm Fans on my heatsink
All Blowing IN
Shall i put 2 blowing and 2 Sucking?

Maybe I missed something in the original translation, but, is this an air or H2O system? If it's air, is water on your heatsink a major problem? If it's H2O, do you really want to introduce bubbles into your tubing???


I'm sure you ment sucking hot air... at least... I think... :D

By the way, I find blowing is much better (hm.... bordering on the limits of the forums with that statment....):rolleyes:
 

hdj

Member
Joined
Apr 5, 2002
Location
new orleans
It depends on the design of the heatsink. In general, If you have a PIN grid on the sink (Alpha pal, swiftech mcx462) You will want to suck the air out.
If the sink has a FIN design, you want to have the fan blowing.