VID (Voltage Identifier) = Voltage Level "request" by the CPU to the motherboard's VR (voltage regulator) to supply it, this is initialized by the CPU and can change accordingly if the CPU is in power saving mode like C1E/EIST features, and also each CPU has an unique max VID internally that was set at factory level while they're running at full load. Turning off power saving features like C1E/EIST will overide and disable those feature and the cpu's VID will be permanently set at their max.
VCore = Actual voltage "delivered/supplied" by the mobo to the cpu, this could be automatic from the cpu as the function of C1E/EIST features ... or ... it was manually set and override by user like in OCing, and this "manually set" vcore could be...