You cannot compare the BIOS Vcore value with one in Windows, as the system conditions are very different (unless fixed voltage is used).
On some systems (Haswell-based especially) Vcore monitoring doesn't work properly, so lots of vendors rather report the VID instead of Vcore. This might be your case as well. Can you please compare the Vcore/VID values shown by HWiNFO side-by-side with GIGABYTE's tool ?