As discussed in http://forums.fedoraforum.org/showthread.php?t=265998  ,
the CPU governor can only be set to "performance" or "userspace". Attempts at adding new ones appear to work, but are not switchable.

Here is the command log that explains this:

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
userspace
# modprobe cpufreq_performance cpufreq_ondemand cpufreq_conservative cpufreq_userspace
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
userspace
# echo conservative > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance
#
 
No other system messages are dumped anywhere - that I can find.