First, from work out of Vanderbilt, a study of 8000 people showed that a gender difference in processing speed began in kindergarten and peaked in adolescence so that girls had a much greater advantage performing under timed test conditions than boys.
Excerpt: "One example of a test requiring processing speed is reading fluency, in which a person reads a sentence and judges its truth value, trying to read and judge as many sentences as possible in three minutes. In such tests, Camarata said, the average accuracy score for teen girls' might be around 50%, while it would be 20% for teen boys."
This could be an important contributor to the Gender Achievement gap because boys have much lower levels of achievement as they progress through K-12 education.
Look at the differences in GPAs for high school grades (girls are the higher curve in purple below)- and yet if you look at the SAT scores, boys have higher aptitudes - but lower GPAs.
If you want to get your blood pressure up, read the entire report Smart Boys, Bad Grades at the link below. The authors present a fairly compelling case some of the causes of boys' academic underachievement. Are "gender-blind" schools really demanding inappropriate expectations of the boys?
In fact, the neurobiology clearly demonstrates that groups of men and women may have different neurobiological preferences in how they approach tasks. In the excerpted figure below, look at the different patterns of brain activation matched for the same performance on IQ tests.
Boys Slower Processing Times
Smart Boys, Bad Grades
Men, Women, Different Brains for Intelligence