Case Fans?

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i am thinking of building a milti-boot case with 4 hard drives plus 2
dvd's and a 600W-or so PSU.  How much should I worry about cooling?
Will case fans do it?  
How many you think?  
A special case?


Re: Case Fans?

On 10/19/2013 05:33 AM, wrote:
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If your hard drives have little space between them, be sure to have fans  
positioned properly to provide them with proper air flow.

Re: Case Fans? wrote:
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A 600W power supply, only provides 600W when it is flat out.
It is the electrical load of the motherboard, video card, and
CPU, that determines the thermal load of the case in a big way.

Mediocre machines, like the ones I build for myself here,
seldom draw more than 150W, and so you don't need a lot of
fans for cooling. I could use a 300W, 450W, or 600W power
supply, and there would still be roughly 150W of heat coming
out of the box. It is the electrical load that counts, like
whether I have an expensive video card or not.

You really need to do a power budget, and work out the total
power. Then, use the enclosure equation to work out the
rough CFMs required for case cooling.


 From some other posting...

    By now, you might be saying, "how can I figure out what fan to
    use for the case ?". Well, there is an equation for that too.
    Now, for this one, you need to know all the thermal loads inside
    the computer case. We have the 125W processor, say a 100W
    video card, two 12W hard drives, say a total of 250W. Our definition
    of a well cooled case, is 7C, which is equal to 12.6 Fahrenheit degrees.
    Plugging in the values.

    CFM = 3.16 * Watts / Delta_T_degrees_F

    CFM = 3.16 * 250W / 12.6F = 62.7 cubic feet per minute.

A typical case fan, averages around 35 CFM or so. The most
powerful fan I've got, is 110 CFM, and you can't sit in the
room while that is running full blast. That's just to give you
some idea what range of fans would work. For a 150W computer,
one rear fan might be close to being enough. For the 250W
computer, maybe two of those fans would be good, in parallel.

I like to position a fan to blow cold air on the hard drives,
but the computer cases don't always make that easy to do.
Currently, my hard drive temperatures are 23C and 23C, to give
you some idea how well my hard drives are cooled. The room is
just a little bit cooler than that.

It's all too easy to end up with seven cooling fans on a
computer. But if you do something like that, sometimes
you'll find that the air is moving backwards through
one of the fans. That's because when you make really
complicated cooling structures, they don't always work
out like you planned them. Stick with a simple front
to back cooling path, and make it so the fans don't fight
one another.


Re: Case Fans?

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Wow!  You never fail!  I should just email you when I have a question.

Zai Xie Xie


Re: Case Fans?

On 10/19/2013 6:33 AM, wrote:
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Drives are not major producers of heat and as long as there is at least a  
little air circulation between them one fan, in the right place, should  
serve you well. I have a Drobo 5N containing 5 X 3tB drives and it has only  
a tiny cooling fan in the back and the drives stay satisfactorily cool.  
Optical drives generate almost no heat and then only when they are  
spinning. The PSU will take care of its own cooling since no other fans  
really contribute much to airflow inside the PSU case. What really  
determines your cooling needs are the GPU(s), CPU(s), and to a lesser  
extent, memory and chipset cooling. If you get into high-performance  
hardware there your cooling needs can get quite demanding. Find a case  
which allows clean unobstructed airflow in the right places and you can get  
by with only a couple of fans with a non-performance system.

Re: Case Fans?

On 10/19/2013 1:30 PM, John McGaw wrote:
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I should have added to the list of things that _really_ make heat the  
low-voltage regulation components which provide the tightly-controlled low  
voltage which actually runs the CPU(s). On a MoBo designed to support  
overclocking these components can put out excessive heat but you can tell  
from the amount of heatsink (and sometimes heat pipes) that the  
manufacturer puts on these parts

Re: Case Fans?

On 10/19/2013 3:33 AM, wrote:
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I think the case design matters more than the number of fans. I like  
Fractal's engineering. Some of their cases have this top mounted fan  
with a scoop attached. The top fan is to pull the heat off the ram.

Note fans blow better than they suck. While people will make all sorts  
of arguments about fan arrangement, I suggest all the fans but one blow  
into the case. If you go with the Fractal, have that top find blow out  
of the case.

Top mounted fans aren't all that unique these days. Antec has them, but  
you need to assure you don't put anything on the top of the case, or you  
use their grill to keep stuff off the fan. I like the ducted scheme that  
Fractal uses better

Their website isn't so great. Too much flash.

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