A look at the difference between T-Mobile's 3G and 'new' 4G speeds

This week, T-Mobile lit up its highest speed HSPA+ networks in Orlando, New York, and Las Vegas, promising a theoretical maximum speed of 42 Mbps downstream. The company expects to deliver this level of service to 25 major U.S. markets by mid-year.

On the CTIA show floor today, we've pitted T-Mobile's 3G and 4G networks against one another on two devices which are nearly identical in design: the Samsung Galaxy S Vibrant and the Samsung Galaxy S 4G.

On the left is the Vibrant, powered by Samsung's 1GHz Hummingbird processor, running Android 2.2 (FroYo), on the right is the unreleased Galaxy S 4G, also powered by the 1GHz Hummingbird processor, and also running FroYo. For this informal speed checkup, the two devices utilized Ookla's Speedtest.net app.

As you can see in the video, the 3G network returns a reading of 4497 kbps downstream and 45 kbps upstream while the 4G network clocks in 8.94 Mbps (9154.56 kbps) downstream and .44 Mbps (450.56 kbps) upstream, or roughly 2.04 times faster downstream, and ten times faster upstream.