I am sorry I forget to mention that my card is EVGA FTW3 flash to ASUS Strix XOC BIOS.
So now I just try using dual BIOS switch to turn back to master BIOS and HWInfo64 can read VRM/VRAM temp again.
But GPU-Z can read VRM/VRAM temp with ASUS BIOS. :(
Try various build till the lastest 5.92-3580. Try reinstall many times. Try restore original order. Try delete HWInfo64 registry. Try looking at GPU I2C Bus Exclusion / Reset GPU I2C Cache. No luck so far.
Also what exactly is VR Loop1 in ASRock Z370 Taichi ?