View Full Version : installing case fans

11-06-02, 03:11 PM
I have just installed two Thermaltake smart fan 2s in my midi tower. One is positioned under the psu attached to the back of the tower (next to the cpu fan). The other is attached to the front of the case at the bottom. I have set the front fan to blow into the case and the rear fan to blow out of the case. I have never used case fans before so I do not no if this is the correct way to position them?

The case temp with no fans and the side off goes to about 28-32 degrees C, the cpu runs about 29-38.

After putting the fans in and closing the case the case temp is 36-42 degrees and the cpu is 38-44.

I expected the temps to be much lower dose it sound ok?


11-06-02, 04:18 PM
You have your fans set correctly. But they are stuggling in getting the heat out of the case. This usually calls for higher rated cfm fans or installing more fans.

Good air flow thru the case is essential and dependant on a number of things. First, each case with system components tends to be different. But basically its like this:

Intake and exhaust cfm's should be about equal. More air coming in is considered positive pressive and more air going out than coming in is considered negative pressure. I generally have more luck with positive pressure setups in mid-towers.

Suggest initially trying a higher rated fan in the front intake...80mm, 36cfm or higher.

Its really trial and error (but fun if you enjoy experimenting). Just remember you can go overboard and have your case sounding like a vacuum cleaner. :D

11-06-02, 05:26 PM
Thanks for the reply Flash
It seems I put one of the fans the rong way round so both the fan were blowing into the case. I have now turned it back and the temp has dropped so now its about 29 33 cpu temp and the case is a bit lower. The fans have speed controls so I can increase the airflow but the fans get very loud. Now I am going to have a play on UT2003 for an hour or three and see what the temp goes to. if it get up to 40+ ill have to turn them up a bit.


11-13-02, 11:50 AM
Interesting reading... I have had my Coolercase Tornado for a while (total 6 fans). The fans were pre-installed when I bought it and it didn't make much difference to temperature over my previous case which only had 2 fans. After reading about you installing the fan the wrong way round, I checked my fans out of curiousity. I have 5 fans sucking in air and one fan blowing it out. I turned around 2 of the fans to make 3 in and 3 out and my processor temperature dropped 9 degrees. Guess you learn something new everyday. :o

11-13-02, 07:16 PM
Been there, done that! :D Great job guys! I find that a lot of times it turns out to be something simple that I just overlooked. Its always best to check things a second and even a third time to make sure you got it right the first time.

Just a while back I put together a system with a mobo I had not used before. Well, I was really being careful hooking up and making adjustments to the components with this mobo. The temps were running a good 6C higher than they should have been. Finally I found the problem, I failed to connect power to the front intake fan and the rear exhaust fan with the psu fan was having to do all the work. :rolleyes:

11-16-02, 01:19 AM
Hey Fred, I recently put 2x sunnon fans on my case. After a bit of experimentation I discovered that the cooling info from Intel is correct. With both fans on the back, the MB temp was 1-2deg cooler than when I put one on the (bottom) front and one on the back (behind CPU). So definately try the fans in different positions and see how they perform. I also discovered that covering the vent holes in the side(top) of the case did nothing for temp readings.

11-20-02, 11:42 AM
Hot air rises, so its best to have fans blowing out towards the top of your case, and fans sucking in towards the bottom. You want to avoid sucking in the hot air you just blew out, so for example, you shouldn't have both suckers and blowers at the back of your case.

I have my suckers on the bottom-front part of my case and the blowers on upper-back. The hot air gets blown our the back of the computer desk. Its a corner desk so it has lots of room. You want to make sure both your suckers and blowers are have lots of room to breathe. If you cable modem is resting right next to a fan grill then your fan won't be doing anything useful.

I also have filters over my suckers and every other vent in my case sealed. That way it greatly reduces the amount of dust getting in. I also have sound insulation all over the inside of the case, which does help with the noise.

BTW. www.nexfan.com is awesome. I got 80mm BB Sunon fans for $1.75 each. I ordered 10 of them :)