How large are my case fans?

Solution
Your case fans are 120mm.
Fan noise comes from the rpm they are running at, not so much the brand or fan design.
Changing out fans for lower rpm units will reduce your cooling.
I might suggest you first experiment with slowing down your current fans.
There are cheap parts that will do this like the zalman fanmate
http://www.newegg.com/Product/Product.aspx?Item=N82E16835118217

If your fans are connected to the motherboard, your motherboard may have some fan controls.
Or try speedfan, a free utility.


You are much nicer then me, I will gladly help others with problems or if they need some expert/experienced suggestions, but not help them be too lazy to do a very simple search, or in this case he could have even just used a ruler.
 
Your case fans are 120mm.
Fan noise comes from the rpm they are running at, not so much the brand or fan design.
Changing out fans for lower rpm units will reduce your cooling.
I might suggest you first experiment with slowing down your current fans.
There are cheap parts that will do this like the zalman fanmate
http://www.newegg.com/Product/Product.aspx?Item=N82E16835118217

If your fans are connected to the motherboard, your motherboard may have some fan controls.
Or try speedfan, a free utility.
 
Solution

I agree! WTF?