BlackOps/Avenger: GTL Ref Table

[Xello]

Could someone explain to the clueless person what this means?

I'm guessing those are voltage adjustments, does that mean that VTT GTL +31 means an extra 0.740v?

You're not actually changing any voltages with the gtl setting, it's a reference value that the motherboard uses to determine if a signal is 'high' or 'low' (1 or 0).