You want a "flow" of air through the case - typically front to back but only because most power supplies already exhaust out the back - so it is best to "stay with the flow" (pun intended).
If you don't want to hear your fans (and I sure don't!) do three things:
(1) Buy a quality case. Better cases will provide lots of "large" (120mm or larger) fan support and help suppress fan noise too. Some even have noise deadening materials lining the interior. I love my Fractal Design R4
(2) Use the largest fans your case supports. Larger fans move much more air while spinning at the same or lower RPM (thus less noise).
(3) Use quality fans. The best fans typically use precision ball or fluid bearings for quiet, vibration free spinning. Plus the fan blades and fan housings are professionally and aeronautically (they are basically similar to airplane wings) designed to grab and push as much air quietly as possible. Cheap fans use cheap bearing and poor designs.
Originally Posted by Dude111
Ya know how it makes your fans quiet??
BY SLOWING THEM DOWN!!!!!
Is that bloody stoopid or what? -- Your fans run FOR A REASON... Slowing them down so they dont work as well IS NOT A GOOD IDEA!!
Alot of stupid things online!!
That is NOT stupid at all! Actually slowing your fans down to make them quieter is a very valid procedure AS LONG AS
you still have enough air flowing through the case to adequately cool the components inside. Fans don't have to run at full, jet noise speeds to properly do their jobs. This is why virtually all (except entry level) power supplies have built in fan speed controllers. Most graphics cards have variable speed fans. And virtually every motherboard controls the CPU fan based on the CPU's temperature. So slowing down the fan speed is not stupid, when done right.
stupid is slowing your fans down without monitoring your temps.