Andreas,
According to the Intel® 64 and IA-32 Architectures Software Developer’s Manual Document, the MSR that sets VR Therm Alert Status (R0) for the processor is MSR_CORE_PERF_LIMIT_REASONS bit 6. This register is valid for the processor based on that document. It's possible that the motherboard's VRMs use different register and for that you will need to check with ASUS. I would recommend to wait for the HWiNFO response, they might be able to confirm if this is the register they use to report in their tool the VR Therm Alert.
Intel® 64 and IA-32 Architectures Software Developer’s Manual: https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf
Amy C
Intel Customer Support Technician
Under Contract to Intel Corporation
