VRs can be off chip (MBVR stands for motherboard VR) versus on chip (FIVR stands for fully integrated VR). In both cases, there exists a protocol called SVID th

VRs can be off chip (MBVR stands for motherboard VR) versus on chip (FIVR stands for fully integrated VR). In both cases, there exists a protocol called SVID that allows the processor to send voltage control commands. The MSR is merely the interface or proxy for these commands.