C1 is the first idle state, C2 the second, and so on, where more power saving actions are taken for numerically higher C-states. C0 is the operational state, meaning that the CPU is doing useful work. Idle States (C-states) are used to save power when the processor is idle.

Intel® 64 architecture delivers 64-bit computing on server, workstation, desktop and mobile platforms when combined with supporting software.¹ Intel 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory. It offers improved manageability by limiting downtime and maintaining productivity by isolating computing activities into separate partitions. Intel® Virtualization Technology (VT-x) allows one hardware platform to function as multiple “virtual” platforms. Intel® Virtualization Technology (VT-x) ‡ Intel VT-d can help end users improve security and reliability of the systems and also improve performance of I/O devices in virtualized environments. Intel® Virtualization Technology for Directed I/O (VT-d) continues from the existing support for IA-32 (VT-x) and Itanium® processor (VT-i) virtualization adding new support for I/O-device virtualization. Intel® Virtualization Technology for Directed I/O (VT-d) ‡

The official marketing text of Intel Core i5-650 processor 3.2 GHz 4 MB Smart Cache Box as supplied by the manufacturer

I5 650 specs