OK I see you are referring to case fans. I also see you have plugged them into the dedicated "fan" connector comming from your power supply. I think these are usually full voltage connectors. Those fans also look clean to me so I doubt they are being slowed down by a lot of dirt. Most case fans that claim to be "quiet" on the package or advertising run purposely at low speed.
My favorite fan is the Thermaltake MadDog MD-TTF-DB-A1357. It's a high speed (4800 RPM) fan with both pot and thermal sensor speed controls. I attach the sensors to my Video card and chipset heat sink. As the demand on my system increases, the fans speed up and they go much faster than typical fans. When I'm at the desktop doing 2D stuf, can't even hear them. When running SH4 they howl. Been using this technique for three years with no heat failure even when over-clocking. Of course my CPU and Vid card have a lot more cooling capacity than it looks in your pic where you have a standard CPU cooler that came with the CPU.
-Pv-
|