Dell Streak 7 owners hoping to use their 7-inch tablet on AT&T rather than T-Mobile have discovered the slate supports HSPA+ 4G on both networks. According to StreakSmart, after the T-Mobile USA carrier unlock is removed, the tablet's modem is revealed to support both 1700/2100MHz (AWS) and 850/1900MHz.
That means HSPA+ on both carriers, as evidenced by the photo above.
Unfortunately, right now there's no free way to unlock the Streak 7; instead you'll have to turn to an unlock vendor like UnlockStreak, which charges $49 for the hack. It apparently won't affect your warranty, and should take 1-3 working days to process.