Have an oldish build, and it's a bit noisier than i'd like.
Asus A8N Premium
Athlon x2 4200
Scythe Ninja + 120mm Antec fan on low.
Seasonic S12 500
It's quieter than the harddisk, but has a steady hum and fan hiss noise - cant locate by ear where it originates as my hearing sucks. The case seems to resonate a bit too much - applying pressure to the side panel deadens the hum - any tips?
(It's not the graphics, can hear that spinup when gaming)
The hiss is probaby the stamped fan grilles and the small doors in front of the filters.
That humming is the Tricool fan as said. Especially the one sitting in the lower "windtunnel" . It hums sligly less by mounting the fan with rubber pegs. But the biggest problem is the plastic fan mount. Some Blue tack or play doo, and some foam strips will fix that to 90 % at least. Best way, is to get a Nexus or Noctua fan(s).