Datasheets are technical documents that are released when a processor family launches and are updated as new information becomes available. They are typically split into sections like the following: Introduction, Features, Electrical Specifications, Package Mechanical Specifications, Thermal Specifications, Signal Description, Electrical Specifications, Boxed Processor Specifications.
Datasheets can vary across processor families to some extent. Usually this document contains areas of interest such as the VID range, processor package assembly information, thermal specifications, thermal profiles, and information on processor power states, etc.
Intel® Pentium® D Processor 800 Sequence datasheet
Intel® Pentium® D Processor 900 Sequence and Intel® Pentium® Processor Extreme Edition 955, 965 datasheet On 65 nm Process in the 775-land LGA Package supporting Intel® 64 Architecture and supporting Intel® Virtualization Technology.