If you are interested in finding out what your CPU is really doing then check out RealTemp.
RealTemp T|I Edition
http://www.overclock.net/t/1330144/realtemp-t-i-edition
CPU-Z is a MHz validation tool so it favors consistency when a CPU is lightly loaded over accuracy. Starting with CPU-Z 1.62, it started reporting lightly loaded CPUs a little differently compared to previous versions. Nice to see that someone noticed.
Most people don't understand EIST because many monitoring utilities have been trying to be just like CPU-Z.
The new version of RealTemp includes a new C States window so you can see exactly what your CPU is doing. It also reports exactly what the CPU multiplier is doing.
If you are interested in saving power with a modern Intel Sandy or Ivy Bridge CPU, I would recommend using the High Performance profile and then enable C3/C6. There is no need to worry that your CPU voltage or multiplier are too high because if C6 is enabled, your CPU cores are mostly asleep anyhow and are getting next to zero voltage. The voltage that CPU-Z reports when a CPU core is idle and using the C sleep states becomes meaningless.
There are a lot of myths about CPU power consumption on the internet. If you own a Sandy or Ivy Bridge CPU, buy a Kill-a-Watt meter and do some testing. Some power profiles can kill performance without saving you anything.
Power Optimization – a Reality Check
http://www.cs.berkeley.edu/~krioukov/realityCheck.pdf