Top case fan question

[peonyu]

Just a general question here, I have a spare 120mm fan and Im thinking of cutting a hole at the top of the case and having that fan help exhaust air from the case. I keep my tower in a cabinet and I believe it will help reduce temps a good bit but im not sure by how much [if any]. Anyone have a general idea of what to expect temp decrease wise from a top 120 mm fan, is it even worth the bother ? I have 3 intake fans and 1 out take right now [2 if you count the psu fan].

 

[Slugbait]

You didn't include case & fans & fan placement in your specs, but my guess is that you are pulling in considerably more air than you are exhausting, and that will give you heat problems before you close up your machine inside a cabinet.

I would do temp readings, then disable one intake fan and read temps again.

 

[peonyu]

I cut the hole out already and got a good 120 mm blowing out. Decreased temps about 4c overall, and the fan is 5v modded so its silent. not a bad deal overall.

My fan placement is pretty heavy on the intake - i have 2 side fans [1 120mm, 1 80 mm] as intakes, and 1 80mm fan on the bottom back of the case behind the lowest pcie slot blowing in. out take fans are 1 120mm in the back of the case by the cpu, and the psu fan + top fan now.

 

[peonyu]

it dropped gpu temps by 20c aswell.