* Dynamically adjusts CPU speed and voltage based on demand for CPU
  (idle/work ratio threshold is user-configurable)
* Automatically detects available processor speeds
* For normal operation, no configuration or options are necessary.  Just
  run it!
* Full multiprocessor support (each CPU separately run-time configurable)
* One binary works on both Linux 2.4 with the 'proc' interface and Linux
  2.6 with the 'sysfs' interface. No need to recompile if you switch kernels!
  (proc interface deprecated)
* Configurable minimum and maximum allowed speeds
* Can minimize CPU speed and voltage if AC power is disconnected from the
  computer (requires ACPI)
* Can maximize CPU speed if AC power is connected to the computer (requires
  ACPI)
* Can minimize CPU speed and voltage if CPU temperature gets too high
  (Requires ACPI, temperature is user-configurable)
* Can be told to lock CPU at minimum or maximum frequency via signals
* "nice()'d" processes and those waiting for I/O will not increase CPU speed
* Polling interval for CPUs, temperature and AC adapter configurable
  separately
* Crash-proof frequency switching even if you have a very tempermental CPU
  and an obsolete version of CPUFreq (some AMD mobile Athlons in particular)
* handles strange processors with lots of little steps
* More that I'm forgetting.