files in /sys/devices/system/cpu/cpu0/cpufreq/ provide information and a means of controlling the frequency scaling subsystem. Seed values are given in Khz. You need to be root to access the /sys filesystem.
Your max speed is at /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq.
# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
Your min speed is at /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq.
# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq