By default all (I think) the profiles use the "ondemand" scaling governor, this is quite aggressive in increasing the frequency under load.

If it bothers you, you can change this to "conservative", which is far less aggressive about increasing the frequency so is more likely to spend time on the inbetween frequencies, for a temporary change as root type "echo conservative >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor".

For a more permanent change save yourself a custom profile (you may have done this already), you'll find it in /home/user/.kernel and change the line in that file that says "GOVERNOR=ondemand" to "GOVERNOR=conservative", and set your custom profile as default.