What is the most effective place to put a case fan?

By hellokitty[hk]
Apr 13, 2008
  1. What is the most effetive place to put a case fan?

    Where should you put your case fans if you had the option of putting it on the side, front or back? (and everything inbetween lol)
    Were would it provide the most cooling?
  2. kimsland

    kimsland Ex-TechSpotter Posts: 14,525

    I say back to suck out the hot air from the CPU
  3. Grafficks

    Grafficks TS Rookie Posts: 302

    Well, if you had enough fans then it would be good to put them in all those aforementioned positions.

    But if you could only choose ONE place to install a case fan, then in my opinion one should definitely choose the rear exhaust fan position. In an ATX tower case, this is located right under the power supply, and is in close proximity to the CPU's HSF, providing extra cooling for the processor.

    This fan mount is present in most cases, and would also provide cooling to the system as a whole because of its relatively elevated position in relation to the rest of the case (warm air rises, convection).

    But if you had enough fans:
    - the front fan would be near the bottom of the front panel, blowing in
    - the side fan would be on the side panel, blowing in
    - the rear fan would be near the top of the back of the case, blowing out
  4. kimsland

    kimsland Ex-TechSpotter Posts: 14,525

    You need to test with this, one way then the other

    I've found that the side fan blowing in can cause issues on the CPU fan blowing in.
    Just through experience
  5. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    I don't quite understand. A stock Intel CPU heatsink fan blows into the heatsink, and a side fan shouldn't cause issues there, if there's space.

    As for the original question, quite definitely the rear exhaust fan. I've wrecked a computer in my earlier years of messing around with computers by installing the fans in the front, sucking air in, and no fans at the rear, thinking that the PSU already had a fan.

    Turned out, it wasn't sufficient at all, and in a year, the PSU burnt out, and took the motherboard with it. Not to mention that it kept overheating.

    Oh well, learnt from it, and hopefully you won't consider any other fan placements, for your solo fan XD

    Btw, it generally is enough to have a solo exhaust fan, although it is recommended that you should have a front intake fan as well. Of all the fans, the side panel fan is the least useful in terms of general PC usage. If you're after absolute lowest CPU temps, its a different story altogether.
  6. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Well, i will probably be playing crysis, so major cooling is probably going to be needed :(

    Well... the Antec 900 has a 200mm top fan. what good is that?

    I think i will have an aftermarket cooler, like a zalaman except the type that is flat against the procesor and the fans stick up away from the procesor.
  7. Grafficks

    Grafficks TS Rookie Posts: 302

    The top 200mm fan on the Antec Nine Hundred is a clever way to exhaust a lot more air while creating less noise. Again, since warm air rises, it makes perfect sense for Antec to put a large fan on the roof of that particular case.
  8. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    Although the 200mm top fan is a great idea, it still does not replace the back exhaust fan. Hot air rises, that much we can agree on, but it does not rise at a rate fast enough. Given the back fan would be much closer to the CPU, it would perform much better in terms of exhausting hot air.

    HOWEVER, If you got one of this, these, or similar heatsink design, you can get away without an exhaust fan, since the fan on these heatsinks will blow hot air straight out. HOWEVER (again), I wouldn't recommend skimping on that rear exhaust fan.
  9. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

  10. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    You kinda misspelt the brand... its Zalman, not Zalaman....

    Btw, the Zalman offering is better, since it is made of pure copper (with a coating...)

    The only reason they would substitute copper with aluminum is the weight. Some larger heatsinks, if they had used copper, would weigh almost a ton....
  11. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Ok so is it better to have a fan that is going up away from the processor or the kind that is flat on it?

    How much power would a casefan have?
    I was considering looking into this fan controller:

    and it says it has up to one amp per fan, is that enough for powerfull fans?
  12. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    FYI, 1 amp is more than enough to kill someone...

    So yes, it is more than enough for powerful fans :D

    Just for comparison sakes, Intel stock heatsink fans are about 0.2 amps, depending on which model you bought (highest I've seen is 0.22 amps on those, but there might be higher).

    I'm not sure how many amps 200mm fans draw though....

    I'd be very surprised if any fan (by itself of course) will draw more than 1amp.

    edit: Bear in mind that some people might link more than 1 fan per knob, which increases the power draw. Might still take more than just 2-3 fans to go over that 1amp ceiling.
  13. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    O.o i could die from a fan controler??!!!

    Are you sure side fans aren't so good?
    It would seem that they blow air directly onto the motherboard and i supose everything on it too.
  14. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    I didn't say its not good. I said that if you had a choice of side compared to anything else...

    If you have spare fans, its worth putting one at the side, if not, having it in front would be better I reckon.

    You might have lower CPU temps, but I reckon cooling your HDDs would be of more value, as they have a higher chance of failure with a higher temp.
  15. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Well i think i might buy a 90 cfm fan and i personaly think that is probably worth more putting it on the side instead of the harddrives.

    Anyway thanks everyone!!
  16. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    Wait, looking at your first post, I'm assuming that you DON'T have a fan anywhere at all at the moment.

    If that is the case, I strongly suggest the BACK of the case, not the front or side.

    That is the most important place to put a fan, as having an intake fan blowing onto your CPU alone will cause hot air to stagnate on other parts of the computer case, which may be more disastrous. A slightly higher CPU temp will not cause any problems, however a burnt out PSU (which will happen, even though your PSU has a fan itself) will be disastrous.

    Also, I'd like to point out to you that ALL cases come with back and front fan placements, but only some, and even then, only the newer cases will come with side fan placements. This is due to the fact that there is already enough cooling for the CPU with a single rear fan, and an extra side fan will further lower the temps, but will not have a huge impact on normal computing (overclockers excepted of course).

    Then again, it is your computer, and if you still feel that a single side fan is adequate for your needs, feel free to do as your please :D
  17. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    lol no i think ill build a new comp really soon so i just wanted to know.

    I do have a back fan, i think i have two, i see two fan slots close to each other but im not sure if one has a fan in it lol.

    EDIT: i don't have a front fan, my comp is 4 years old.

    Ok well i gues we can pretty much end this thread then.
    Thanks :)
  18. kimsland

    kimsland Ex-TechSpotter Posts: 14,525

  19. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    okay, just making sure you DO have rear fans.... :D

    And that pic... I've seen others like it, I think its just excessive. The noise generated.... I reckon if you used it for a year or something, you'd go deaf :D:D:D
  20. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Woa Wtf Lol
  21. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,427   +27

    I believe in the fact that you can never overcool a PC but that pic takes it a bit too far. ;)
    As for the fan, the first priority would be to place it so it sucks hot air out of the case and throws it out the back. Next would probably be some fans in the front and lastly, a fan or two on the side panel.
  22. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Well that many fans is too much. Might as well use an entierly liquid cooled system.

    Ive heard of some guy with a -40C case. WTF?! wouldn't the cold actualy damage the parts?!!
  23. Traverse

    Traverse TS Rookie

    bring air in from the front, send it out the back. :)
  24. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Topic Starter Posts: 3,424   +142

    Ok i got it now.

    Back fan DEFINETLY.
    Yes to a front fan.
    Sure if you have a side fan :).
  25. CMH

    CMH TechSpot Chancellor Posts: 2,039   +9

    The chips in our computers aren't designed to work in both extremes of temperatures.

    But then again, which overclocker lets anyone else determine what parameters our chips are supposed to work with? :D:D:D

    Our chips definitely can work outside those parameters, but to work at -40C continuously might not be good for the chip, although I don't see why....
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