Does affirmative action actually affect college admissions that much now?

I went on college.mychances.net just for fun to see what they thought my chances were at getting in at some colleges. I am hispanic so I indicated that in my profile. It said that I have a 68% chance at getting into University of Penn. Just out of curiosity I changed my race to caucasian. It then said I had an 11% chance of getting in. I have a hard time believing my race affect my admission chances that much. Is race currently a big deal in college admissions or does it not matter that much?