Question about CPU speed

Hello,

CPU-Z is reporting:

Name: Intel Core 2 Duo E8200
Code Name: Wolfdale
Tech 45nm Core Volt 1.120
Intel Core 2 Duo CPU E8200 @ 2.66Ghz

Core Speed 1995.0 Mhz
Multiplier X 6.0
Bus Speed 332.5 Mhz
Rated FSB 1330.0 Mhz

Can you help me understand why the speed is 1995.0 Mhz instead of 2.66Ghz?

My Motherboard says it supports 1333 bus, but is the CPU going at its potential?

Enhanced Intel Speedstep Technology. It's a feature that reduced voltages and clock speeds to conserve power. When in idle states or using very little CPU power, EIST will kick in and bring the voltages and clocks down.

When your PC needs more raw power, your voltages and clock speeds will go back to default.