air duct or side fan?

nomannoman pakistan
edited October 2004 in Hardware
how much difference does a side fan make to cooling..(if casing has a rear fan)

also how much effect does a duct(from side onto the cpu)in a case have on cooling...also is it necessary to have a fan at the opening outside or is it ok to let the heatsink's fan suck the air from outside?

the thing is... i have to make a choice between two
casings... one is ugly but has a side fan...the other
is goodlooking but does not have a side fan...although
there are tiny holes on the side...

i think both have air ducts on the side
so could u guys suggest something? :scratch:

Comments

  • muddocktormuddocktor
    edited October 2004
    noman, you can always add a side fan to your case, using a metal nibbler or a dremel tool with cutoff wheels to cut the hole in the case side. I don't know what you can find there in Pakistan but I imagine you should at least be able to find the nibbling tool. I just use a wire fan grille to measure the size hole I need to cut. That way you can buy the good looking case and add a side fan to it. I use a dremel tool with cutoff wheels personally .
  • edcentricedcentric near Milwaukee, Wisconsin Icrontian
    edited October 2004
    A side hole, another fan just like the one on the CPU heatsink, a few cable ties, duct tape and a plastic or cardboard tube. This will get fresh air to your cooler and also increase airflow since the cpu fan will be pulling against less back pressure.
    The tube shouldn't be sealed against the cpu fan, just close to it.
    You will get better performance if you put 'flow straighteners in the tube. Pieces of stiff paper work fine. Make sure that they can't come loose. The last one that I made used a paper tube from a roll of toilet paper and file folder stock for the vanes. You had might as well block the cneter, the fans don't move air there. If your fans have 4 blades use 5 vanes, if the fans have 5 blades use 7 vanes, this will make it quieter. The vanes should be within 1 cm of the fans.
  • GnomeWizarddGnomeWizardd Member 4 Life Akron, PA Icrontian
    edited October 2004
    Yea i would go with the side fan Ducting isnt all its cracked up to be
  • JChretienJChretien Vancouver, BC, Canada
    edited October 2004
    vanes? what do you mean by vanes... picture please ^^
  • edcentricedcentric near Milwaukee, Wisconsin Icrontian
    edited October 2004
    When you look down hte tube, in the direction of air flow you are looking at the edges of flat pieces that run the length of hte tube (like a star). The air comming off of the fan is trying to spin. If it is spinning when it hits the second fan then that fan is less effective.

    The reason for hte vane numbers is that if you have the same number as fan blades then they all pass at once and you get a noise.
  • nomannoman pakistan
    edited October 2004
    hi...

    plz also tell me...how much important(for cooling) the side fan is....or how much difference does an airduct make(to cpu temps)?...
    I don't know what you can find there in Pakistan but I imagine you should at least be able to find the nibbling tool
    .

    the casings i was talking abt do have ducts already made..(intel 38 C or somthing)
    currently i am not planning to mod the case myself.......If i want to mod...i will find some tools or somthing...and ask you guys details abt the mod..

    you guys are telling a hell lot of science(edcentric)... :eek:
    This will get fresh air to your cooler and also increase airflow since the cpu fan will be pulling against less back pressure.

    so you are saying that i should use a fan on duct as well as the fan on cpu?? what happens if i dont use fan on the duct...how much of a loss that would be?

    and about the fan on side....

    where do i place it..if i want to mount my own fan...
    should it be in the center of side panel or at the lower corner?
    (i guess if i put it in centre i might get some cooling for harddrives...may be.. :scratch: )

    and.... a casing has two side fans...but one rear fan and one psu fan....will the air flow be balanced?

    finally....
    is the temp reduction by extra side fan worth the noise they make?

    shower me with the blessings of your knowledge :thumbsup:
    alrighty then
  • nomannoman pakistan
    edited October 2004
    uhmm...anybody there??????? :shakehead
  • GnomeWizarddGnomeWizardd Member 4 Life Akron, PA Icrontian
    edited October 2004
    In my opinion Yes if you get a low noise fan that produces decent CFM's it is worth it since it pulls in the cold air directly onto the cpu and or vid card
  • nomannoman pakistan
    edited October 2004
    after i posted all the above things..i browsed a lot..
    according to shormedia guide....two rear fans do overall best job...but rear fans+side fans are one of the worst performers :eek:

    then comes the pressure bullllshi t. some ppl say positve is better and some say negative is better....what then??

    and if i use two rear exhaust fans...what abt the intake?...

    Kindly reply my qustions of previous post and this one also...
  • GnomeWizarddGnomeWizardd Member 4 Life Akron, PA Icrontian
    edited October 2004
    Most people that mount thier own fan do so just above the vid card and in around 3 to 4 inches from the back of the case. Best case cooling is fan in front blowing in and 2 fans in back blowing out. thats standard if you put a side fan in dont put a freakin 60 cfm fan in since it will create pressure cause its pushing so much in the back to cant exaust it. IF you can try and custom fit 92mm fan in hte side panel bigger more cfm and quiter. Me i have a 120mm in hte front blowing in a 120 mm in hte back blowing out my psu fans blow out and the 92mm fan in the side is disabled since i dont use it ( WC )
  • MediaManMediaMan Powered by loose parts.
    edited October 2004
    PC airflow and heat - a cooling guide:

    Enjoy
  • nomannoman pakistan
    edited October 2004
    hi, media man...
    i have read the guide...
    i want to know...you have said in the guide that two rear fans is overall best performance...my question is about the intake...
    will the intake be from all the various vents and holes in the casing....or.....i need a fan for intake?

    plz also tell me about the effectiveness of the air duct..
  • MediaManMediaMan Powered by loose parts.
    edited October 2004
    Noman,

    I've done the kabillion fans in a PC case. I had access to hole saws and, holy crap, did I drill holes in PC cases. At one time I had 15 or 17 fans in a PC case. It's just something you gotta do if you have the equipment for it and the fans....and a Saturday with nothing to do.

    The case wasn't loud but the sound was dominant. It wasn't a shrill high pitched sound from the high speed fans...but with that man fans it did have "presence."

    I have found that the most effective first line of defence is to remove the hot air from the case and do so in one direction or combined rear and top blowhole.

    If you were to choose between JUST an exhaust or JUST an intake..the exhaust fan would do much more for overall cooling effect. Blowing cool air into a case isn't as effective as removing the hot air from a case.

    Also...two lower RPM fans will move more CFM at a lower db than one high powered fan thus saving your listening sanity.

    You may also try to make your exhaust CFM at a greater ratio than intake CFM. EG: 40 CFM exhaust and 20 CFM intake. You don't want to build up pressure in your case thus swirling the air around and disrupting the path it will take.

    Hope this helps.
  • nomannoman pakistan
    edited October 2004
    it does help :)

    what about the airduct? like the one in intel recomended casings...i think its called 38c or something.....
    how much of difference it will make to my cpu temps?

    secondly..

    a=......2 rear fans+airduct on cpu/hsf.
    b=......1 rear fan+1 sidefan+airduct on cpu/hsf.

    now....
    strictly speaking....nothing more,nothing less...........................
    which of the ABOVE TWO,in your opinion is better...?? :scratch:
  • MediaManMediaMan Powered by loose parts.
    edited October 2004
    a
  • nomannoman pakistan
    edited October 2004
    how much of difference airduct makes to cpu temps?
  • MediaManMediaMan Powered by loose parts.
    edited October 2004
    Well you asked for nothing more,nothing less answer. :p From what I remember about airducts, and I've tried a few ghetto ones myself, they provide 5-8 degree Celsius drop in temperatures versus no fans at all. (No fans does not include the PSU fan which is always present)

    BUT....

    I don't know how effective they would be when combined with other exhaust fans.

    You may find that, and these are just blue sky made up numbers...


    A) Case just PSU fan = 60 C IDLE

    B) Case with 1 or 2 exhaust = 52-55 C idle

    C) Case with cpu duct only = 52-55 C idle but warmer mobo and peripherals

    D) Case with exhaust plus cpu duct = 50 C.


    That's my blue sky guess.
  • nomannoman pakistan
    edited October 2004
    hmm...

    i also thought somewhat like that....
    if i use a duct ,and exhause fans too...that would be good idea...
    although i would like to believe that side fans are effective...but i don't think they really are....right? the cooling they will provide to my cpu area can be provided by duct too...and it would be silent :D

    anybody else out there who has used duct alongwith exhaust fans?

    alrighty then.....
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