The Intel Core 2 Duo processor class is the successor of the Core Duo with a longer pipeline, 64 Bit support, a fourth decoder, an amplified SSE-unit and an additional arithmetical logical unit (ALU). Because of these improvements the Core 2 Duo CPUs should be 5-20% faster than a evenly clocked Core Duo.
As the name suggests, the Core 2 Duo lineup consists out of CPUs with 2 cores. They feature 2, 3, 4 or 6 MB Level 2 Cache (2 and 4 for Merom CPUs, 3 and 6 for Penryn).
Each CPU features eX Bit (Execute Disable Bit) technology, SSSE3 (SSE4), Enhanced Speedstep support. Some models also feature virtualization support (VT or Vanderpool called).
The mobile Core 2 Duo is identical to the desktop Core 2 Duo processors, but the core voltage of the mobile CPUs is lower (0.95 versus 1.188 V e.g.). Furthermore, a lower front side bus (FSB) is used to save power. Therefore, the laptop versions are a bit slower.
The energy need of the processors is marked by pre-set letters in front of the type designation (number).
X … Extreme (fastest) version with the highest current consumption
E … >= 55 Watt (Desktop PCs)
T … 30-39 Watt (Standard laptop CPUs)
P … max 25 Watt
L … 12-19 Watt (Low Voltage)
U … <11.9 Watt (Ultra Low Voltage)