But we're not talking about the PSAT.

That said, PSAT math scores go up from the mean by ~3.25 standard deviations.

SAT math scores only go up ~2.5 SDs, meaning that this very popular exam isn't terribly discriminating at the top. If we were to put this in terms of IQs, this would mean that the SAT equates an math ability score around 150 with one around 138.

Sources: PSAT SAT