Some facts:

1) Whites on average have a 15 point higher IQ than blacks, across many different studies.

"There is a long-standing 15 point or 1 standard deviation difference between the intelligence test scores of African Americans and White Americans, though it might have narrowed slightly in the then recent years. The difference was largest on those tests, verbal or non-verbal, that best represented the general intelligence factor (g)."

Source: American Psychological Association

2) IQ across different ethnic groups in the US: Blacks have an average IQ of 85, whites of 103, Asians 106 and Jewish Americans 113:

The study found that the average IQ for African Americans was lower than those for Latino, White, Asian, and Jewish Americans (85, 89, 103, 106, and 113, respectively; Herrnstein & Murray, 1994, pp. 273–278)

Source: University of California and University of Western Ontario

3) Overall, 18% of Asians have an IQ over 120, 10% of whites do and only 1% of blacks. Nearly 84% of blacks have an IQ below 100, which is slightly below the average IQ for whites. The ratio of white Americans to black Americans who have an IQ over 125 is 30:1.

The IQ gap between blacks and whites in the United States—15-17 points—has not changed since it was first measured nearly a century ago. Both races’ test scores rose during the century, but the gap remained as large at the end of the century as at the beginning despite considerable social change.

Source: University of Delaware

4) For those who claim that IQ tests are biased against blacks and that's why they keep getting lower scores, there are IQ tests like the Raven's Progressive Matrices which don't have any language and rely entirely on visual pattern recognition. It's simply finding patterns in visual shapes. Even then there is a marked difference between black and white IQ scores, not only in America but internationally as well, like in South Africa between white and black engineering students:

Source: University of Johannesberg

5) Harvard psychologists took a look at how black children adopted by well off upper-middle class white families at a very young age perform on IQ tests once they grow up in white families with good socioeconomic conditions. Black children adopted by white parents average 89 on IQ tests at age 17 (slightly better than the 85 average for blacks nationally). White children who grew up in the same households and had white biological parents on average scored 109. Even with the same socioeconomic upbringing, the racial IQ gap remains.

The Minnesota Transracial Adoption Study examined the IQ test scores of 130 black or interracial children adopted by advantaged white families. The aim of the study was to determine the contribution of environmental and genetic factors to the poor performance of black children on IQ tests as compared to white children. The studies' general findings were that the IQs of children of a particular race did not differ significantly depending on whether they were raised by their biological parents or by adoptive parents of a different race. The gap between black and white IQ scores remained even if growing up in the same family.

Source: http://en.wikipedia.org/wiki/Minnesota_Transracial_Adoption_Study

6) East Asian countries have on average the highest IQ scores. African countries have on average the lowest. European countries are generally between the Asian and African countries.

Source: http://www.statisticbrain.com/countries-with-the-highest-lowest-average-iq/

7) From the higher education achievement perspective: In 2012, the mean critical reading SAT score for college accepted students was 428 for blacks and 527 for whites. For mathematics, it was 428 for blacks and 536 for whites. For writing it was 417 for blacks and 515 for whites.

Source: US Department of Education

8) From the elementary education achievement perspective: At both the grade 4 and grade 8 level, there is a persistent achievement gap between whites and blacks in both mathematics test scores and reading test scores in ALL states.

Source: 2007 US Department of Education National Education Assessment

9) Intelligence is highly linked to genetics:

Estimates in the academic research of the heritability of IQ have varied from below 0.5 to a high of 0.8. (where 1.0 indicates that monozygotic twins have no variance in IQ and 0 indicates that their IQs are completely uncorrelated) Various studies have found the heritability of IQ to be between 0.7 and 0.8 in adults and 0.45 in childhood in the United States.

Source: http://en.wikipedia.org/wiki/Heritability_of_IQ#Estimates_of_the_heritability_of_IQ