If you could sustain that performance, you'd download a two-hour "HD" movie in the space of ten seconds, AT&T claimed.

However, the operative term is "if." As we witnessed first-hand with our tests on Verizon's network (disclaimer: that's our parent company), reaching those speeds is currently unlikely with any provider. You need a millimeter wave connection that's rare, especially indoors where the signals fall off quickly. And of course, this is a hotspot device. It's not yet clear how well the tech will fare in phones with built-in 5G. This does show the potential of 5G, but it could be a long while before you can expect this kind of performance outside of ideal conditions.