I think with the CPU fan speed stuff, you might need to have CPUSPEED running. FC5 installs that by default.. I think it both reduces the CPU clock and fan speed to keep the CPU cool.. But I don't use it.. The high CPU fan speed doesn't bother me..
You may also need the download the Cool'n'Quite utility from the AMD website..
Quote from the AMD Site..
AMD Athlon™ 64 Cool'n'Quiet Driver Version 1.50.03 Linux - AMD Athlon 64 Cool'n'Quiet Driver Version 1.50.03 for Linux 2.6 series kernels. Provides support for AMD Cool'n'Quiet technology for Linux systems. Adds support for 2.6.10 and later kernels. Requires cpufreq-1.20, cpuspeed-1.20.1, or powersaved-0.8.19 or later to support SMP and dual-core systems.