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Fan arrangement help please. 3 exausting, 1 intaking?

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JacksonVFR

Technical User
Oct 2, 2003
81
US
Hello. I almost was reluctant to post this question, because I usually only save this forum for my most difficult of problems, which you guys have helped bail me out on many times! This question is a bit more superficial.

I run two Maxtor 80GB hard-drives that get a little hot and am trying to cool them. My case is an Aspire Dreamer II and I have two stock 80mm fans running in it, one intake, one exaust. I'm running an AMD Athlon XP 2800+ with stock fan and heatsink and have no real temp problems with it. This time of year it's been running 30c-38c. The hard-drives get heated though. I have plenty of 80mm case fans laying around.

I found a picture of my case on Newegg and added a little info to it with mspaint. Can you guys help me place some fans? I was thinking of adding one to the front (exaust) and one to the back (either intake or exaust, not sure)?

(Note: I tried a fan in the front earlier and noticed it is much quieter on exaust than intake. It's of course cooler on intake, with air blowing directly on the hard-drives, but seems to be cosiderably cool enough either way. I'd like to keep this cool yet quiet).

 
In most cases you want the intakes low and the exhausts high.

The answer has always been 42
 
I am assuming that the fans are one in the side & one on the back panel. As franklin97355 posted what the normal recommended air flow pattern is and you are currently running cool, I would not suggest that you make major mods that might disrupt the current flow.

As it is your HD's that are hot, address that directly. There are many addons for just this. Some passive, some active. I have moved to placing 3.5" HD's in enclosures that take a 5.25" drive bay but there are other reasons I do this.

Look at the passive, for complete quiet, as these provide a substantial heat sink to draw & disperse heat away from the drive.

Optionally, a 3.5 HD fan system provides air flow directly to the drive using internal air thus not upsetting the overall flow pattern.

You case looks as though the back panel will accept a 120mm fan and there are several quite modls available.These move more air and some are very quite.

Bottomline, cool your drives directly and not by trying to increase to overall air flow to accomplish this. To much risk to upset the whole cart.

Some examples:

I-STAR iStorm 8 Series Hard Drive Cooler

Spire FlowCooler HD05010S1M4 Hard Drive Cooler

Titan TTC-HD12 60mm Deluxe HDD Cooler

Enclosure
AOC UHDC Ultimate Hard Drive cooler

VANTEC MRK-102FD-BK

Hope this gives you a place to start

rvnguy
"I know everything..I just can't remember it all
 
Some general, rough guidelines:

Try to ballance overall CFM (volume on intake approximately equal to the amount exhausting)

Front lower to back top: natural convection dictates that air rises so it goes without saying you don't want to set fans fighting against this process, thats why all the fans low down in the case are best drawing in cool air (intakes) and all the fans higher in the case are best (Exhausting)

Bigger fans spin more slowly and move more air, at the same time they make less noise.
Generally bigger fans are better (you will notice the trend towards bigger fans being fitted as standard.

leave a gap between those two hard drives, positioning them so the fans blow either side of the drives.

Power supplies with a large 120mm fan or secondary 80/92mm fan mounted directly above the CPU heatsink, are best at helping draw off the warm air from the CPU.

Personally I fit fewer, larger fans (just two 120's ATM) as opposed to 5/6 smaller noisier ones
Martin



We like members to GIVE and not just TAKE.
Participate and help others.
 
Usually" a front, lower (intake) fan and a back, upper (exhaust) fan are enough. If not then you can try a couple of different combos:

1. Put Floppy in lowest 3.5" bay. Move and mount a hard drive in the other 3.5" bay (where the Floppy had been). Install a double or triple fan in the lower 5.25" bay (where current hard drive was removed and relocated to the 3.5" bay)and leave the other hard drive in the bay above where it is already residing now). This keeps air flow steady without causing too much turbulence but still cooling the drives.

2. Another solution is to move the Floppy to the bottom 3.5" bay and install a double fan unit to the bottom of the lower 5.25" bay hard drive bracket with the hard drive installed there also. This increases the air space between the HDD and Floppy, yet allows a low profile fan setup to help cool.

Too many or too powerful case fans cause too much current fluctuation and "usually" too much turbulence within the case for effective/quiet cooling. A good CPU/fan, GPU/fan, backcase/fan, frontcase/fan and HDD/fan should be sufficient for proper operation.

 
Lots of good advice here, now my two cents.

1. Airflow is key. Make sure that the flow of air through your case is as unobstructed as possible. That means using rounded cables instead of ribbon cables, and making sure that cables are routed out of the direct airflow.

2. Intake should be on the bottom of the front of the case, exhaust at the top of the back. Others have explained why.

3. Someone mentioned balancing the fans, but didn't explain more detail. You want to look at the CFM ratings for each fan and try to balance it out so that input CFM is as close to output CFM as possible. If your exhaust fans push out significantly more than the intake fan draws in, then you will be drawing in air from other patchs (the nooks and crannies of your case seams), which could lead to lots of dust and other junk being sucked in, as well as disrupt the air flow. If you pull in more than you push out, you will also disrupt airflow, potentially even worse than in the first scenario. Needless to say, if the air does not flow efficiently throughout the case then you will have cooling problems.
 
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