I am going to install two additional fans in my case (Centurion 5 CAC-T05 US). It already comes with an 80mm intake at the front and a 120 mm at the rear.

I will install another 80 mm at the front for intake and a 90mm on the side. Question: should the side fan be exhasting air, or drawing it in?

Also, does the CPU fan blow air onto the CPU/cooling fins, or does it draw warm air away?

Finally, what is the situation with respect to airflow direction for the graphics card: does the fan blow air on to or away from the card?

Heya Jackpine,

I did a whole lotta testing to see which worked best. I recently installed a Thermalright SI-120 heatsink with a 120mm fan. I also have a 120mm at the front bottom to suck air in, and a 120mm at the rear top sucking air out. There is an additional 80mm on the side blowing air onto the CPU fan. With all the combinations, I had lowest temps with the side fan blowing down onto the CPU fan, and the CPU fan blowing down also. You would thin (because of the SI-120 design) that this would increase the temps...but due to the panaflo volumes (CFM) it cools a lot better . I have a fairly warm room and the airflow around my PC is pretty poor, but with this combo, I have about 35-36°C on idle and 50-55°C at full load.

With graphics, I used to have a standard fan (PCI-x ATI X800GTO 256MB) but it kept overheating. I installed an ArcticCool AT4 which does the trick. They are also the new standard for the X1900 series etc (I think). The trick seems to be blowing air OVER the heatsinks on the card, and then out through a grill at the back (which came with the fan).

Also, here is the discussion I had a while ago on the same topic......
http://www.bleepingcomputer.com/forums/ind...29&hl=suck+blow

Hope that helps!!!

Thanks JP. I also checked out the thread that you mentioned. I need to digest all this information before I start screwing in the fans.

Another advantage of blowing cooler air INTO the vanes is that it produces a lot less static than sucking warm air through the vanes... Static collects dust and dust blocks vanes and reduces airflow over claggy fan-blades...

The side fan was originally designed to blow cool air directly onto the heatsink for the scorching P4 processors. (If you're running a Pentium, you might notice that it's usually directly over the processor.) Rather than using already-heated inside air for the heatsink fan, the cooler outside air would theoretically be better. (Though there may not really be much difference.)

OK, so... my case has two grid openings on the side. One of them is directly in-line with the cpu, and has a funnel attached. Should I take off the funnel and attach a fan, and then the funnel to the fan?

The second grid opening is below this one. Should a fan be attached there as well?

If I need to install 2 fans, should they both be intake? If yes, will the exhaust fan be of sufficient capacity to remove all the air?

Do I need to install filters on intake fans?

I duct the cooler outside air into my case directly onto the CPU cooler (with a funnel-like cone) - and it makes a world of difference with the Prescott P4's!

I got a 3º C decrease by cutting a blowhole in the top of my case.

Yes for the filters on intake fans.

Probably not. Many modern cases have lots of grids to allow free flow of air out of the case. And you're not gonna like all the noise.

The way I ran my fans in my new case was to pull air in from the back of the computer and pull air in from the front. This was done to cool 2 very warm parts of my PC the HDDs and the processor. Most important is to look at the case design decide critical parts and adjust the temperatures accordingly.

As for my exhaust I have none due to the fact that may case is currently open sided on 4 sides (no sheet-metal on front, back and sides). However when the case gets sided (very soon hopfully) I will have exhaust in the top center mobo side between ODD's and PSU. there will also be an exhaut on the Mobo side near the HDD's and 3 new intake fans 2 on the opposite side of the case and one dead center on the top.

And all will be 80 mm fans.