Enhanced Intel SpeedStep® Technology

Enhanced Intel SpeedStep^® Technology enables OS to control and select P-state. The following are the key features of Enhanced Intel SpeedStep^® Technology:

Multiple frequency and voltage points for optimal performance and power efficiency. These operating points are known as P-states.
Frequency selection is software controlled by writing to processor MSRs. The voltage is optimized based on the selected frequency and the number of active processor IA cores.
- Once the voltage is established, the PLL locks on to the target frequency.
- All active processor IA cores share the same frequency and voltage. In a multi-core processor, the highest frequency P-state requested among all active IA cores is selected.
- Software-requested transitions are accepted at any time. If a previous transition is in progress, the new transition is deferred until the previous transition is completed.
The processor controls voltage ramp rates internally to ensure glitch-free transitions.

Note: Because there is low transition latency between P-states, a significant number of transitions per-second are possible. All of Processor Cores must be in the same P-state at any given time.

Intel® Speed Shift Technology

IA Core Level 1 and Level 2 Caches Intel® Speed Shift Technology