How many fans are needed?

[WayTooShort]

Well I'm building a computer, and I was just wondering how many fans are needed? I already have two, one in GPU and one in CPU, is one for the rest enough?

Also if my power source has a fan, does that only work for it or for the other things too?

 

[UndeadDragon]

You will need a fan in the back of your case, otherwise the hot air will just be circulating inside the case. How high specced is the computer?

 

[Slapshot136]

your CPU fan works only for the CPU - it puts hot air back in the case, thus you can disregard it
your GPU fan usually does the same, or atleast blows some hot air back into the case
your PSU fan will suck air out of the case, but it isn't designed to cool more then the PSU - this won't bring cold air to anything
normally you would want atleast 1 extra fan in the back to push air out (so as to not overwork the PSU by having it pull hot air and be unable to cool itself),
and 1 in the front to pull air in (having 3 exhausts and no intake = the exhaust fans fight each other)

 

[WayTooShort]

Thanks, I bought two more fans.

Now I have another problem; I have retardedly gigantic CPU heatsink and a fan with it The fan has two 4-pin connectors and one 3-pin connector. Is it enough if I just apply the 3-pin to motherboard, or do I have to also apply both/one of the 4-pins to PSU?

Also only second one of the 4-pins has actually pins, rest are just holes.

 

[Slapshot136]

im not sure what you are talking about here (pictures/models would help), but if the fan spins with only 1 plugged in, that's all you need - the rest are likely for reading the fan speeds/changing them while running

 

[WayTooShort]

The 3-pin is wrong counterpart, but otherwise the cooler's cables look like this picture:

It has two 4-pin things in same cable and one 3-pin thing without pins (the motherboard has its counterpart with pins)

And now I noticed that where it read "CPU FAN" in motherboard there is actually a small 4-pin, different from the 4-pin in the cooler. The 3 pin fits into it, does it work? Then there are three 3-pins, "PWR FAN" "CHA_FAN1" and "CHA_FAN 2". What are those for?

Also I'm worried about the cooler since it weights almost 800 grams (1.7 pounds) and is 20 centimetres (8 inches) tall, is the motherboard alone enough to support it?

The cooler has its fan in the side instead of being on the top, so I can choose which direction I aim it. Should I turn it towards the exhaust case fan in the back (there would be 1 centimetre (0.4 inch) space only) so it would go straight out, or should turn it to some other direction?

 

[sqrage]

>>It has two 4-pin things in same cable and one 3-pin thing without pins (the motherboard has its counterpart with pins)

That is indeed a 3pin. However, the other two are usually not referred to as 4pin connectors. They are male (with pins) and female (receives pins) Molex cables. Usually these are provided with fans in case your motherboard doesn't have any available fan connectors. Molex cables are plugged into the PSU as opposed to the motherboard. This removes the ability to control the fan's speeds manually. Seeing as how you have the 4pin connector available on your motherboard, you can go ahead and plug the 3pin into that. No need to worry about the molex.

>>The 3 pin fits into it, does it work? Then there are three 3-pins, "PWR FAN" "CHA_FAN1" and "CHA_FAN 2". What are those for?

Yes. CHA 1 and 2 are chassis fans. The rear exhaust fan and perhaps a side, top or front fan.

>>Also I'm worried about the cooler since it weights almost 800 grams (1.7 pounds) and is 20 centimetres (8 inches) tall, is the motherboard alone enough to support it?

It shouldn't be a problem. The mounting systems usually balance the weight between different points in the motherboard so it doesn't strain it too much.

>>The cooler has its fan in the side instead of being on the top, so I can choose which direction I aim it. Should I turn it towards the exhaust case fan in the back (there would be 1 centimetre (0.4 inch) space only) so it would go straight out, or should turn it to some other direction?

I would definitely point it towards the rear exhaust fan.

 

[WayTooShort]

Thanks for the detailed reply, that cleared most of the things. However, I'm still thinking about pointing the cooling fan towards the rear fan. There is only 1cm (0.4 inch) gab between those two 120mm fans, could they possible affect each other so that they would spin faster than they should, causing them to break?

 

[sqrage]

No that wouldn't happen. But if the CPU fan is stronger than the exhaust fan, it might "clog" (blow more air than it can push) the exhaust fan and lower its efficiency a lot.

 

[Slapshot136]

No that wouldn't happen. But if the CPU fan is stronger than the exhaust fan, it might "clog" (blow more air than it can push) the exhaust fan and lower its efficiency a lot.

this is true, but also the CPU fan connects to the motherboard such that you can change the speed of the CPU fan if needed - it is still best to have all fans in the same direction, generally front to back, with possibly an extra exhaust at the top

 

[WayTooShort]

this is true, but also the CPU fan connects to the motherboard such that you can change the speed of the CPU fan if needed - it is still best to have all fans in the same direction, generally front to back, with possibly an extra exhaust at the top

Well, I think the CPU fan is uncontrollable and always running at max speed, since it has only 3-pin connector when motherboard has 4-pins.

Anyways I just moved the fan to the other side of the heatsink - it's still blowing to same direction, there is just more space between it and the exhaust fan.

But I have another problem; My PSU's fan is only 2 cm (0.8 inches) away from the CPU heatsink, can it have some negative side effects? Like PSU blowing hot air to the heatsink, causing it to warm up too much?

Also now that I changed the fan to other side, a metal thingy connecting the fan to the CPU heatsink is also touching the motherboard heatsink. Can the heat from CPU travel to motherboard and cause problems?

 

[sqrage]

>>But I have another problem; My PSU's fan is only 2 cm (0.8 inches) away from the CPU heatsink, can it have some negative side effects? Like PSU blowing hot air to the heatsink, causing it to warm up too much?

No, the PSU fan blows air out of the case, not into it.

>>Also now that I changed the fan to other side, a metal thingy connecting the fan to the CPU heatsink is also touching the motherboard heatsink. Can the heat from CPU travel to motherboard and cause problems?

Can't exactly picture what you mean here, but it shouldn't be a problem.

Btw, you probably can control the fan, you'd just need a program to do it, but it's not really necessary.

 

[WayTooShort]

Thanks for your reply, again. I don't have my RAM yet so I could boot the system and test fans and stuff like that out, but I don't want anything to blow up on the first try either.

About the cooler, I found out that it's Scythe Ninja or something like that. Here is a picture of it:

I was talking about those metal wires that keep the fan attached to the heatsink, on the other side it touches the motherboard heatsink. But I now that I think about it, I doubt that it's thick enough to actually transfer enough heat to cause problems, though I'm not a physicist in any degree..