I figured it out. I had to be connect to some kind of hot spot. I tested it again, not in the same place, but inside my house with wifi turned off. And the Captivate only got 0.46 while the Moto G got 1.6. Moto G still won, but neither had really high speeds. I was in a soccer field in the middle of the night watching fireworks during the first test. I assume wifi auto connected to something and gave me really high speeds. I didn't think to turn wifi off because I assumed there wasn't any around me to connect to.