The processor uses six voltage identification signals, VID[7:0], to support automatic
selection of power supply voltages. Table 2 specifies the voltage level corresponding to
the state of VID[7:0]. A ?1? in this table refers to a high voltage level and a ?0? refers to
a low voltage level. If the processor socket is empty (VID[7:0] = 11111111), or the
voltage regulation circuit cannot supply the voltage that is requested, it must disable
itself. The Voltage Regulator-Down (VRD) 11.0 Processor Power Delivery Design
Guidelines For Desktop LGA775 Socket defines VID [7:0], VID7 and VID0 are not used
on the processor; VID0 and VID7 are strapped to VSS on the processor package. VID0
and VID7 must be connected to the VR controller for compatibility with future
processors.