Core 2 Quad
Core 2 Quad processors are multi-chip modules consisting of two dies similar to those used in Core 2 Duo, forming a quad-core processor. This allows twice the performance of a dual-core processors at the same clock frequency in ideal conditions.
Initially, all Core 2 Quad models were versions of Core 2 Duo desktop processors, Kentsfield derived from Conroe and Yorkfield from Wolfdale, but later Penryn-QC was added as a high-end version of the mobile dual-core Penryn.
The Xeon 32xx and 33xx processors are mostly identical versions of the desktop Core 2 Quad processors and can be used interchangeably.