Does not getting enough sleep affect SAT score?

On the PSAT, I had a 760 on verbal junior year and scored 800's on all the practice tests. On the SAT last May, I figured that I would easily get an 800, so I didn't really care the night before and stayed up late watching tv. I got probably 5 hours of sleep, and I'm the type of person that needs at least 9-10 hours to function during the day. The first part of the SAT I was alert, but by the second part my eyes were faling asleep and I had to really strain to read the pages. I only got a 650 on cr, and when I got the diagnostics back, the ones I got wrong were apparently because I didn't read the question carefully enough to see specificaly what it was asking for. I figured this was because I was half asleep on the verbal sections, how much sleep should I get next time?