Low Vid means less voltage for lower OC's = Less resistance to heat (Higher temps).

High Vid means more voltage for lower OC's = More resistence to heat (runs cooler).

Low Vid and High Vid all come together when they are near the OC limit = Same OC results when comes down to top end clocks (4500-5000Mhz).

So your choice is between a low OC with less volts or a high OC with lower temps