How much difference can one fan make?

[crsgardner]

I finished a new build recently: AMD Athlon 64 3200+, Radeon Pro 9800, RAID SATAm etc. It runs warm when open: 35 degrees Celsius on average. It burns up when closed: well over 50 degrees (it even approached 60 once).

The case currently has 4 fans: 1 on the power supply, 1 on the CPU (AMD stock), 1 on the GPU and 1 in the front of the chassis. There's a place on the back of the chassis for a fan, which is listed as "optional" in the case's instructions. I've already purchased a 120mm (hopefully quiet) fan from Newegg, but I have a question: what difference can one fan make? Is it really going to be keeping the temperature under 40 degrees Celsius (like I'd want it to)?

 

[Jaxidian]

I don't know if it will keep you under 40 but it will likely make a big difference. Right now, you really have nothing pulling the hot air around your CPU out of your case other than the PSU, a little bit.

 

[saxophonoia]

it will get the hot air out which is probably what you need, so yes it will be helpful

 

[jagec]

depends on the fan...but I'd say pretty much every computer will want a fan in the back.

 

[HardWarrior]

Fans, depending on their positions and velocity can make a huge difference, espeacially exhausts positioned towards the top of the case. When you take the door off can you feel a plume of hot air escaping the case?

 

[crsgardner]

When you take the door off can you feel a plume of hot air escaping the case?

Do I ever. There's definitely a good deal of heat coming off the CPU fan. My guess is that the hot air is pooling right where the rear chassis fan should be (optional my butt). I'm going to stick a 120 mm in there and see if I can get some cross ventilation.

 

[HardWarrior]

"Optional=Go ahead and buy the damned thing now and get it over with!", my wife. If just a cross flow doesn't get the job done consider a top-mounted blowhole (120mm if you've got the room). Mounting one made a appreciable difference for me, even with high ambients.