Gigabyte Z77M motherboards: No VCore adjustment
Gigabyte makes several similar MicroATX motherboards with the Intel Z77 chipset:
The only difference between the Z77M-D3H and Z77M-D3H-MVP appears to be Lucid Universal MVP support (GPU virtualization). There doesn’t appear to be any hardware differences, but since Gigabyte re-used the same photo for both boards, I can’t be certain.
The more-expensive Z77MX has essentially the same feature-set as the other two boards (including Lucid), but it’s clear there are hardware differences. One major feature available on the Z77MX but not the Z77M is manual voltage adjustments (VCore and GFX).
I decided to test whether this was really a hardware limitation or a feature disabled in the BIOS. I flashed my GA-Z77M-D3H-MVP board with the GA-Z77MX-D3H BIOS. The Z77MX BIOS booted up correctly on the Z77M and there were more settings available in the BIOS menus, including VCore. Unfortunately, the VCore adjustments had no effect. Darn.
The GA-Z77M-D3H-MVP uses an Intersil ISL95836 PWM chip to control VCore and GFX voltages. Comparing photos of the Z77M and Z77MX suggests that it uses a different PWM chip (small square chip center-right edge of board). This suggests that the changed chip is for the extra programmability needed for manual voltage adjustments on the Z77MX, while the Z77M boards probably use the standard method of directly connecting the processor’s VID output pins straight into the PWM chip’s VID inputs.