Intel's high-end Pentium 4 processors produce a lot of heat. If your CPU fan regularly runs at maximum speed despite being regulated by the motherboard, the CPU cooler might be insufficient. My Scaleo X with AMD 5200+ X2 (Dual-Core) had an idle temperature of 40-45° Celcius and could peak 58-60° on load with the stock CPU cooler, AVC Z8UB015.
The maximum temperature AMD's AM2 processors may reach is 65° Celcius.
Anyways, The cooling capacity of the AVC cooler is very bad, and the CPU fan has a maximum fan speed of 4500 RPM, which results in high noise level. After replacing the CPU cooler with CNPS9500
the idle temperature dropped to 26° Celcius and load temperature dropped to 35° on lowest fan speed (1350 RPM with fan controller).
I would recommend high performance fans and a fan controller, like the Zalman Fan Mate 2
. That way you can choose your fan speed, and hence the noise level too. Replacing CPU cooler may help too. If the cooling capacity is good the CPU fan won't need to run at maximum speed.