Intel EIST SpeedStep

Intel’s SpeedStep Technology has origins tracing back to the
days of the Mobile Pentium 3 and Pentium 2 processors with Geyserville
Technology. However, at that time, the 1GHz Pentium 3 model was the
fastest and required 1.7V for operation, and its maximum power
consumption was 34W! Since that time, many of the processor technologies
have been phased out and have brought new features in the Pentium 4,
Celeron M, Pentium M, and most recently the Core Duo series. However,
over six years later SpeedStep Technology remains in their mobile
platform as well as some Pentium 4 and Pentium D processors. At hand
today are the results from our most recent (EIST) Enhanced Intel
SpeedStep Technology investigation.

Check out the full article over at Phoronix.