Theoretical Absolute Lowest Temperatures for Airflow

I've been running some tests over here at my Ghetto Labs and have become quite interested in this. No matter how many fans you add to a case, there's going to be a point where it just won't cool it anymore. This is what I am calling the Theoretical Absolute Lowest Temperatures for Airflow.

Now, there's a simple way to determine this Theoretical Absolute Lowest Temperatures for Airflow temperature. Remove the side panel of the case. Grab the best large fan you have in the house, and run it as fast as it goes pointing directly at the case. I’ve determined that the speeds can vary on the fan. I’ve used 1 fan, and changed the 3 speeds on it and still reached the same temperature. This temperature is the lowest you’ll ever achieve in your case and therefore the Absolute Lowest Temperature. You can run IDLE and LOAD tests to get your results.

Now put the side panel back on. Turn all your case fans on (or on high for some of us) and run IDLE and LOAD test to get your results. If you are happy with those results and they are not too much higher than stop there, otherwise keep reading.

If you are unhappy with those results and you think that there is room for improvement within the case for cooling, then start doing some things. Do each step, run some tests to see how much difference it makes

AirFlow
Some of you may not know, but the air should be brought in by the front intake fans and exhausted by the back exhaust fans. Make sure your fans are pointing in this direction.

AirFlow #2
This may seem very trivial, but make sure your computer is on a flat surface allowing the front of the case plenty of room to breath.
Also, make sure the back of your case has plenty of room to throw out the hot air. (Do NOT put it in a corner or a cubby hole)

Case Cleanup
Grab some Zip ties, Some Rounded IDE cables, some double-sided tape, anything that will help with this. Get as many wires out of the way as possible. Put them to the side, behind your motherboard, beside the hard drive racks, anything to get those cables out of the way.

Improve Airflow
You know those pre-made holes in the back of the case for the case fans to push air out of? REMOVE THEM! These limit the amount of air getting pushed out of the case. Remove these and add some nice Grills. You can also do this to the front of the case.

Cut them out


Pop on the Grill


Improve AirFlow #2
Get some faster case fans. (I’m not going to get into buses) Get more if your case is able to hold them. Faster = Better airflow.
Get a PSU (Power Supply) that has dual fans. These help A LOT!

Hope these help.

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If you are still unhappy with the results compared to the Absolute Lowest Temperature, you might want to look into getting a new case all together. As for me, I’ve got my case down to 1*C difference between the 2 temperatures without being too loud.

Any questions, comments, tips, feel free to post.

Thanks,
Hurk

I saw the title of this post and said "OH NOES!"

I thought it was gonna be someone begging to know how cold they could cool a proc with this hsf if temp was that ambient.

Boy am I pleasantly surprised. =)

I heartily agree with routing cables - not only does it improve airflow, but it actually makes servicing your box much less of a chore.

Yeah, it does. I've actually made some changes since then to get those wires out of the way aswell. It's great heeh.

Nice write up Hurk, very informative. I wish i would have not gotten in a hurry and forgot to cut the fan grills out on my new case before throwing all my goodies in it. But I guess that will give me something to do on a rainy day, LOL


Do you think a PSU with one 120mm fan is just as good as two 80mm fans?????

also I have read that it helps to have a little more exhaust than intake is this true??

No. What's good about the dual fan ones, is that there's a fan underneath the PSU and on the back of the PSU. Heat Rises and it get's sucked up by the bottom on, and exhausted by the back one.

More exhaust than intake, I haven't heard this, but I will give it a try. Maybe someone else here has a point of view on this.

Yes more exhaust than intake works best. If reversed the flow of 2 exhaust fans so they would be intake fans and temps rose about 5 degrees farenhiet...I made them exhaust again and temps went down

Did you move them, though? My Antec has 3 80mm fan positions in front(1 for the hd caddy, 2 below it), and 2 in the back below the psu, as wells as a dual fan psu. I originally had the case set up with 2 exhausts below the psu (and the psu exhausts), and 2 intakes (one below the hd caddy at the bottom, one on the hd caddy).

Experimenting one day, I removed the upper/middle exhaust fan and moved it to the middle intake spot, and my temps dropped a few degrees.

I think best pressure orientation actually is arrived at on a case by case basis. (Pun intended.)

Here is something i found to work alot better than the basic airflow thing..
I used to have 2 80mm front bottom intakes. 1 80mm back bottom intake(blow on video card but dosetn change any temps) 3 80mm back top exhaust(counting psu) and 1 92mm blowhole.. well i tried messing around and i turned every fan as an intake besides the psu and blowhole.. now i hav 5 80mm intakes the 92mm blowhole and the psu exhaust with a thing i made deflecting the hot air upwards so it's not sucked back in by the intakes... This dropped my temps like 2-3°c from the basic airflow config.

wait, i think i have found a problem. If you take off the side of the case and blow a fan in it, the air is fighting to get out because its going in only one direction... now if you in some way made it so that air could flow through the case, i think your Theoretical Absolute Lowest Temperatures for Airflow will lower.

stan03 said:

wait, i think i have found a problem. If you take off the side of the case and blow a fan in it, the air is fighting to get out because its going in only one direction... now if you in some way made it so that air could flow through the case, i think your Theoretical Absolute Lowest Temperatures for Airflow will lower.

Click to expand...

There's so much air pushing in, it just flows over and then out of the case. It is the most air coming in.

q149 said:

Here is something i found to work alot better than the basic airflow thing..
I used to have 2 80mm front bottom intakes. 1 80mm back bottom intake(blow on video card but dosetn change any temps) 3 80mm back top exhaust(counting psu) and 1 92mm blowhole.. well i tried messing around and i turned every fan as an intake besides the psu and blowhole.. now i hav 5 80mm intakes the 92mm blowhole and the psu exhaust with a thing i made deflecting the hot air upwards so it's not sucked back in by the intakes... This dropped my temps like 2-3°c from the basic airflow config.

Click to expand...

This seems like a great idea for people that have blow holes on the top. I would do this if I had one. Pulling cold air from around the case and shooting it out the top while it's rising anyways. Great tip.

Bump for more tips!

120mm psu's own any 80mm psu.. they are quiet, and they intake all of the hot air from around the socket of the motherboard and exhaust it out the back of the psu.. sparkles new line of 350w's has this option, and its the best ive seen.

Well I have a normal case with a side fan and 2 fans in the back; The side fan is an 80mm fan blowing air in, and I have 2 in the back; 1 aluminum 80mm blowing air out positioned right by the cpu fan, and 1 80 mm fan under it. So I have my intake fan blowing air towards my motherbaord withbounces back to the case window and mixes with the cpu fan air and then gets sucjed out by the 2 in the back..

Well lets put it this way, this morning i turned on my PC after my A/C had been running all night, went into the biso and my temps read

2c case
8c cpu

in theory....bah, to hell with thoery

Just talking normal air here. No AC or anything. Room temperature. The difference between the 2 temps is the deal.

my pc was idling last night at 23° (rainy night).... i was like cause i never tought i would ever reach those temps on air, let alone in a country as hot as this one

my computer runs 2C higher when A/C is turned off....

though this thread has some good points, i have to point out that the theory laid out above is fundamentally flawed. Even if you push 500cfm into the side of your case, you may actually get lower temps with the sides put back on and moving about half the air (guestimating). if you have good placement of fans then you can create a "windtunnel" effect that will pass more air over components. this is a more effecient cooling method. granted 95% of people here would get better temps using the big assed fan, it isnt necessairily the "theoretical absolute lowest temp". the crevices and metal frame would redirect more air cooling power from that "big fan" than you would think.

my case is a good example. i can take a room fan and blow it at the case with all the pannels off. when everything is on and fans are at max, my general temps are 2*c cooler on both cpu and temp probes on hd's in the case.

the key is allot of medium volume fans.

if you put 2 tornado's in the case it moves allot of air mathamatically, but not over much of the case.

if you have say, 10 fans that push the same air, you will get more even movement of air and eliminate "hot pockets" that heat up other components. lets not even get into the static pressure issue