Also in Houston here, also had AT&T 3G service. I doubt they were throttling your old phone - their local 3G network is just that bad. Using AT&T's LTE network in the same town is rather like using a different carrier. Even the HSPA they built on top of their old 3G is remarkably better. And it's considerably faster than Verizon's current LTE offerings, which have been degrading in speed/quality since mid-April. (Though that might improve in time, and MaBell's service quality might go back down as more people upgrade to it.)