How Many Case Fans Should I Run?

Discussion in 'Build Your Own PC' started by Mike7, Jul 8, 2011.

  1. Mike7

    Mike7

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    For my computer case I have a very tall old server type case that has 2 fans in the front and 2 fans in the back. My new video card is an EVGA GeForce 6200 without a fan but I called EVGA and the rep said that it runs so cool it doesn't need a fan. My power supply is a thermaltake 420 watt top mount with a good built in fan. My processor is and Intel P4 2.26.

    I have the Intel active monitor program that beeps if my computer gets too hot. Most of the time I just look at the internet but sometimes I play video games for a couple of hours or more at a time.

    I don't run any air conditioning in my home just window fans to save money one the electric bill but I am having a big problem with my computer case getting full of dust.

    In my computer case I have two 80mm fans in the front and two 80mm fans in the back. For a while I was running all 4 fans all the time thinking the cooler my computer runs the longer it will last but running 4 case fans fills my computer full of dust too fast. So I have installed two toggle switches (with soldered wires) so I can turn the case fans on or off as needed. The case fans have built in lights so I can easily see if they are on or off. I have my main HDD mounted horizontally in a rack right behind the front top case fan because I figured the cooler the HDD is the longer it will run.

    For just looking at the internet do you think I can get by with leaving all my case fans off in the summer? I don't run much heat in hear in the winter time. I only use fire wood for heating so I am sure I don't need case fans on cold days.

    If need to run case fan(s) all the time anyway should I have just a front case fan or just a rear case fan stay on all the time or should I have one front and one rear case fan stay on all the time?

    When I play video games I plan to turn all the case fans on.
     
    Last edited: Jul 8, 2011
  2. jdeb

    jdeb

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    Your going to want at least one rear fan working to draw the hot air of the case. Find some filter material and figure a way to place it in the area of the air intake (front fans).

    Do you know the model of the case?
     
  3. Khalil

    Khalil 计算机超级技术

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    To be safe with those fanless video cards I would make sure there is an intake front fan installed and as Jdeb suggested a rear exhaust fan, they do get rather warm not only when you are gaming with them!

    Case fans use very little electricity
     
  4. Mike7

    Mike7

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    Thanks for the advice. I was thinking that the power supply fan would draw the air out of the back of the case.

    I do like to browse the internet with a high pixel rate like 1280 x 1024 and a dpi setting of 192 that puts a load on the video card.

    I can't find a brand or a model number on my computer case but it looks just like this one with 2 fans behind the lower front case louvers (besides the 2 case fans in the back below the power supply) and 4 DVD or CD bays behind the top door.
    [​IMG]


    Right now I am using my backup computer an Emachine T1860 with an AMD Athlon 1800 CPU, and a Jaton FX 5200 video card with no fan on the video card. The computer has no case fans and no temperature warning. Do you think I should jury rig an exhaust fan on the side of the case or might that be too much of a load for my 250 watt power supply? I played a video game (Freedom Fighter) for about 3 hours to break in the new video card before the 30 day warranty ran out and it did not seem to over heat.
     
    Last edited: Jul 8, 2011
  5. Khalil

    Khalil 计算机超级技术

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    Last edited: Jul 8, 2011
  6. glc

    glc Forum Administrator Staff Member

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    That also might be a Chieftek case.
     
  7. Nuclear Krusader

    Nuclear Krusader Mondsreitersmann

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    Or Thermaltake Xaser.

    I had a machine in a Xaser and I ran 7 fans on it. But essentially all you have to do is to run more fans that are exhaust. The rule is E = I + 1, where E is number of exhaust fans and I is the number of intake fans. This in order to create a negative pressure inside the case that will push the hot air out. Note that the PSU fan(s) count as exhaust.
     
    Last edited: Jul 9, 2011
  8. jdeb

    jdeb

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    get some thin filter material from antec or cooler master and some thin velcro. Cut 4 small velcro squares and place the velcro on the four corners of the filter material. Stick the 4 female portions of the velco on the exterior of the case frame (between the front panel and case frame)where the intake fans are...in front. You will have to remove the front panel to clean the filters occasionally.

    or spend 40.00 and buy an antec v200 case
     
  9. SARGE

    SARGE The Preacher Man

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    Panty hose makes a good filter.
     
  10. Mike7

    Mike7

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  11. Nuclear Krusader

    Nuclear Krusader Mondsreitersmann

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  12. jdeb

    jdeb

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    that would work real well, of course a little better tape job:D
     
  13. Mike7

    Mike7

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    Thanks for the link.
     
    Last edited: Jul 10, 2011
  14. David M

    David M Techphile.

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    By putting a positive pressure in your case and having filters over the inlet fans your case will stay much cleaner. With a negative pressure dust gets drawn in through the cracks. There are all kinds of filter elements you can buy such as that for household heaters, vacuum cleaner bags to car air cleaners to most any sort of air filter element you can find.

    Since you only have a 420 watt PSU, which is not much waste heat wise, I would consider two inlet fans with filters and one outlet fan. To test the pressure put a piece of Saran Wrap over a crack and see if it gets drawn in or gets blown away.
     
    Last edited: Jul 10, 2011
  15. SARGE

    SARGE The Preacher Man

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    I used to try and find the #1 spark plug firing that way with my thumb over the hole. Time has erased the memory. I either got drawn in once or twice, then blown out once or twice. Never can remember the sequence.
     
  16. glc

    glc Forum Administrator Staff Member

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    There's a tradeoff with positive pressure - cooling is not as good. I personally use negative pressure with intake filters and don't have a major dust issue.
     
  17. Mike7

    Mike7

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    Thanks glc, so how do you define negative pressure, what should I do to get it, and how can I be sure I have it?
     
  18. glc

    glc Forum Administrator Staff Member

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    ;)
     
  19. Mike7

    Mike7

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    I see with positive pressure it would be like a vacuum cleaner and quickly fill with dust.
     
  20. David M

    David M Techphile.

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    Not if like I said the inlet fans have filters. This way ALL the air going in has already been filtered. With a negative pressure, a portion of the air going in through any cracks, seams or holes has not been filtered.

    This is how clean rooms work. Highly filtered air is blown into a room at slightly higher than atmospheric pressure. The slight positive pressure prevents doors etc from admitting contaminants into the room. It is also how biological contaminants are isolated, but the concept is reversed by putting a slight negative pressure in the room which isolates contaminants to that room. The exhaust system has UV light, scrubbers and other devices which kill or remove biologicals.
     
    Last edited: Jul 11, 2011

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