They boost potential quite a bit. I was going through 150 vocab words in 2 hours every weekend when studying for the SAT on them. Normally it'd be around 50 words a day - TOPS
My question would be about how the long term learning is effected. That is to say, if you take a bunch of college kids, track what they remember about their courses say, ten years later, it was found the 4.0 students did not remember the course work as well as the 3's and 3.5's, the idea there being the 4.0's in general used a style of learning that was for the moment to pass the tests but soon forgotten for the latest course work, whereas the lower grade students were learning more for the long term.
It would be interesting to know how well you would remember the words you learned at that rate of 150/day ten years from now as compared to your former 50 word/day skill level. Say you had an identical twin, identical IQ's and such, you take the Nootropic and your brother not. Then come back in ten years and see what percentage of the original you and your brother remembered. Would there be a difference in what you remembered?