Possible dumb question, but I'm not familiar with Androids

[EarthRyno]

I've been looking in to just buying a Sensation and unlocking it for at&t (my current network that I'm locked in with), but I found some people tried to unlock the Inspire for t-mobile and said they didn't have access to the 3G or 4G. They only got 2G.

Would unlocking this t-mobile phone for at&t still allow me to access the 3g and "4g" signals on the phone?

 

[E-POTS]

not on this phone (htc sensation) its missing the 3G bands 850 and 1900 needed to work on ATT...but 2G will work