Today users require the power of simultaneous computing found in a dual-core processor. The Intel® Pentium® D processor brings this power to the desktop. An Intel dual-core processor delivers consumer value by providing additional computing resources that expand the PC's capabilities and provide platform-level advancements for consumers in the form of higher throughput and simultaneous computing. With an Intel Pentium D processor users may perform multiple tasks such as digital rendering and gaming all while running virus scan or other background tasks seamlessly.. It has great features for digital home computing, such as support for EM64T to enable the system to address more than 4GB of system memory and advance security functionality thru Execute Disable Bit that can prevent certain classes of malicious "buffer overflow" attacks when combined with a supporting operating system.
Source:Overclocking the Intel® Pentium® D 805 Processor (Dual Core for the Masses)