Sign in with
Sign up | Sign in
Your question

CPU fan question about airflow

Tags:
  • Heatsinks
  • Fan
  • CPUs
  • Overclocking
  • Product
Last response: in Overclocking
Share
June 12, 2006 11:02:30 PM

should the fan blow air out of the heatsink (running a thermalright xp-90) or should it blow air into the heatsink??

Cuz I just installed it and I can see the antec logo on the fan.. does this mean it's blowing air out and not on the cpu?

thx

More about : cpu fan question airflow

June 13, 2006 12:02:36 AM

You wat to blow air through the heatsink, not suck air out of it. Look at the blades on the fan. One side will seem to be a cutting edge. This is the edge that 'cuts' into the air and pushes it over the rest of the blade.
Related resources
June 13, 2006 12:22:58 AM

does it make a big difference if the fan blows air out and not into??
June 13, 2006 3:30:58 AM

If the fan is blowing towards the CPU... and I put my hand over the fan.. should I feel a good amount of air? or should I feel a slight breeze (and I mean really slight)

Because right now, i'm feeling a pretty good amount of hot air coming out of it.. althought it's not a huge amount.. is this normal?
June 13, 2006 4:07:47 AM

Quote:
If the fan is blowing towards the CPU... and I put my hand over the fan.. should I feel a good amount of air? or should I feel a slight breeze (and I mean really slight)

Because right now, i'm feeling a pretty good amount of hot air coming out of it.. althought it's not a huge amount.. is this normal?


Your statement is confusing. If the fan is blowing towards the CPU, as it should, you should feel a slight suction if your hand was over it. Careful about the fingers. Hot air should come out the sides of the heatsink, unless it is directional and then it should come out in that direction. And yes, a pretty good amount of air should be leaving the heatsink, usually the more the better.
June 13, 2006 4:17:07 AM

If I don't feel any suction.. does this mean the fan is installed backwards??

Is there any way I can know for sure without removing it.. like if the logo of the company is facing towards me (I mean I can see the logo.. not the bearings) does this mean it's pushing air towards the cpu or towards the case?
June 13, 2006 4:25:47 AM

Put a piece of notebook paper next to the fan. If it gets sucked towards the fan, you're good. Usually, if you can see the logo it means it's installed properly.
June 14, 2006 11:04:44 AM

Quote:
Usually, if you can see the logo it means it's installed properly.

False!

Just light up a cigarrette and see if the fan is sucking all the smoke. If not, turn it.
June 14, 2006 11:08:30 AM

Quote:
Usually, if you can see the logo it means it's installed properly.

False!

Just light up a cigarrette and see if the fan is sucking all the smoke. If not, turn it.If he smokes. :wink:
June 14, 2006 11:18:54 AM

Quote:
Usually, if you can see the logo it means it's installed properly.

False!

Just light up a cigarrette and see if the fan is sucking all the smoke. If not, turn it.If he smokes. :wink:
Sure :) 
June 14, 2006 11:33:50 AM

usually the side with the wire is the side where the fan blows air.
June 14, 2006 6:03:28 PM

Did you see the word "usually"? And check this out. I'm seeing a lot of logos on those fans.
June 14, 2006 8:00:16 PM

I didn´t want to insult you...but you leave me no other option. You´re a little dumb.
He has a thermalright.
He bought a separated (not a stock or meant to that specific hs) fan.
Standalone fans have the logos and stickers where the cables pass(usually).
The fans that have stickers and logos are specific for their hs.
Just open your case and see for yourself.

Just don´t try to find or show me one or two fans with logos on front to contradict (is this word right?) me, because I know that almost all fans are like I said.

Cheers.
June 14, 2006 8:17:55 PM

Quote:
I didn´t want to insult you...but you leave me no other option. You´re a little dumb.
He has a thermalright.
He bought a separated (not a stock or meant to that specific hs) fan.
Standalone fans have the logos and stickers where the cables pass(usually).
The fans that have stickers and logos are specific for their hs.
Just open your case and see for yourself.

Just don´t try to find or show me one or two fans with logos on front to contradict (is this word right?) me, because I know that almost all fans are like I said.

Cheers.


1. I guarantee that I'm smarter than you.

2. Did you notice that you used the word usually and the phrase almost all? Pretty much the same words I used in my post. According to you, those are dangerous words. Can I insult you now?

3. I don't have to open my case to see my fans because I have a side window. Guess what? Of the six fans in my case, every single one of them operates like I said. By the way, they are from 3 different companies and all are "separated".

4. I won't try to find "one or two" fans with logos on the front. It's apparent to me that your fear being contradicted. (Yes, it's the right word.) I won't shatter your fragile ego any further by throwing facts at you.

Good day.
June 14, 2006 9:03:31 PM

To go back to the thread, the fan should blow down into the heat sink. This not only works better because it's taking cooler air (further away from the motherboard) into the heat sink but also blowing air across the motherboard, after it passes through the heat sink, to cool the motherboard itself.

As to checking the direction of the fan... c'mon this is so simple that you should be able to think of numerous ways, smoke (match or cig), paper or tissue, look at the fan as it's stopping and see which way it's rotating and pushing the air (look at the scoop in the fan blades).
June 14, 2006 9:27:15 PM

Umm...When I get home...I'm flipping my fan...

Oops.
June 14, 2006 10:32:45 PM

Im going to start off by saying that I actually use the heatsink in question here(XP-90), and it actually is a non-directional heatsink, meaning that it is just as effiecnt as blowing air into the heatsink as it is pulling air through it. having said that which works better for you depends on your case, the fans used and a host of other issues, in my case, the cpu fan lines up almost perfectly with my side vent, and I have 2 intake fans feeding towards the heatsink, thus I tend to run 3-4C cooler if I am pulling air through the HS instead of pushing air into it(down to about 12C over ambient on air). but like I said, it comes down to the case, I would imagine that in most cases you dont get lucky like I did with the location of the CPU in relation to the side vent. so do some testing, flip the various fans and test out different setups, and figure out which works best for you
June 14, 2006 10:33:32 PM

Your fan has arrows on it indicating rotation and airflow directions.

Your fan should blow down onto the heatsink. It also cools the immediate area around the CPU, as in the voltage regulators.
June 14, 2006 11:10:44 PM

Quote:
Im going to start off by saying that I actually use the heatsink in question here(XP-90), and it actually is a non-directional heatsink, meaning that it is just as effiecnt as blowing air into the heatsink as it is pulling air through it. having said that which works better for you depends on your case, the fans used and a host of other issues, in my case, the cpu fan lines up almost perfectly with my side vent, and I have 2 intake fans feeding towards the heatsink, thus I tend to run 3-4C cooler if I am pulling air through the HS instead of pushing air into it(down to about 12C over ambient on air). but like I said, it comes down to the case, I would imagine that in most cases you dont get lucky like I did with the location of the CPU in relation to the side vent. so do some testing, flip the various fans and test out different setups, and figure out which works best for you
I've read the reviews of the Thermalright XP series fans, and they ARE multidirectional to within 1C. Reversing the fan on them, thought , kind of negates one of the XP's great benefits - Wide wingspan. Having the fan blowing towards the mobo helps cool the MOSFETS, and chipset. Nice advantage. I'd rather have my CPU 1C or 2C warmer, and my MOSFETS cool, then my CPU a little cooler and the MOSFETS hot. That will cause instability, as easily as a hot CPU, and shorten the lifespan of the caps, and MOSFETS as well. :wink:
June 15, 2006 3:38:58 AM

yeah, im aware of those issues, but the way the XP-90 sits on my mobo, i dont have overhang on the MOSFETS side, so that argumet is moot point for my case, but i have an intake fan in close proximity to that side of the heatsink(it hangs over the RAM, and i cant reverse it because the heatpipes would push up against the RAM badly), and to be fair, the stock heatsink has exactly zero airflow to the MOSFETS, so one would imagine that something like that would be taken into consideration in the manufacture of the mobo. Also, since I dont OC my computer, they arent under any extra stresses.
June 15, 2006 4:38:17 AM

Quote:
yeah, im aware of those issues, but the way the XP-90 sits on my mobo, i dont have overhang on the MOSFETS side, so that argumet is moot point for my case, but i have an intake fan in close proximity to that side of the heatsink(it hangs over the RAM, and i cant reverse it because the heatpipes would push up against the RAM badly), and to be fair, the stock heatsink has exactly zero airflow to the MOSFETS, so one would imagine that something like that would be taken into consideration in the manufacture of the mobo. Also, since I dont OC my computer, they arent under any extra stresses.
Granted, in your situation, it sounds like direction is irrelevant, but overclocking isn't the only thing to put stress on mobo components. Take, for instance, when P4 Prescotts were first released and guys were putting them on their Northwood compatable mobos. Not all mobos could handle the high current draw of the Prescott(even in some boards that claimed to be Prescott ready), and MOSFET's and capacitors were hitting outrageous temps. Any electrical component, does not like heat, and the more cooling, the better...even if they run at 30C....more cooling won't, in the least, hurt. Something that a lot of people overlook...Some manufacturers included. :wink:


PS. Even if the caps, and MOSFETS aren't "directly" under the HS, the airflow will hit the mobo and flow between components, and still provide added cooling.
June 15, 2006 11:59:26 AM

Quote:


2. Did you notice that you used the word usually and the phrase almost all? Pretty much the same words I used in my post. According to you, those are dangerous words. Can I insult you now?

Good day.


So...you said that usually the logo comes up in front of the fan.
And I said that almost all (usually) are like I said. Logo on the back.

What´s wrong with my sentence?
June 15, 2006 12:57:53 PM

Quote:
I didn´t want to insult you...but you leave me no other option. You´re a little dumb.


Sure you had other options... you just chose to be abrasive. There's no need to be insulting to make a point - in fact it tends to cheapen your argument.

It's rather pointless arguing about where logos are located... Anoobis has it right.
June 15, 2006 3:15:28 PM

Yeah, you're right. I had just got out of bed... :oops: 
!