I don’t believe your little mountains. Look at the one for Native Americans. I believe these are skewed and wrong.
The graphs come from nfs.gov (National Science Foundation report "Scores by Race/Ethnicity"), who I presume got the data direct from College Board. Believe or disbelieve all you want.
In that same report, they also have the test scores in Excel spreadsheet form. See the raw white scores (appendix 1-19) versus the black scores (1-21). Hispanic(1-22) and Native American(1-23)
In 1992, from 1-19, out of 680,806 white test takers, 30,396 (4.5%) got a SAT math score of 700 or above. Among the black test takers, only 430 black students nationwide, (0.4% of the black total), got 700 or above. Among Native Americans, 110 students (1.7%) got 700 or above.