You aren't allowed to discriminate based on race, and as we all know some races do better on IQ tests than others. Basically this rule:
> A selection rate for any race, sex, or ethnic group which is less than four-fifths (4/5) (or eighty percent) of the rate for the group with the highest rate will generally be regarded by the Federal enforcement agencies as evidence of adverse impact
https://www.uniformguidelines.com/uniformguidelines.html#18
It means that for tests with disparage impact you need good evidence that it is actually relevant, good luck proving that for IQ tests. So either you need to design an IQ test which doesn't favor any race, or you need to design an IQ test which looks like work so you can convince a court that it is relevant for the job. College can be seen as an example of the later.