The headline feature is the claimed 867 Mb/s figure for its performance on the 5 GHz frequency band, when using an 11ac router. This is listed because the theoretical maximum for a single antenna transmitting using the AC specification is 433Mb/s. The W900U contains two antennae and therefore its maximum theoretical bandwidth is 867Mb/s (not 866Mb/s as the numbers are rounded to the nearest integer). See also Group test: what’s the best wireless router? The adapter itself is light in weight, just 19 g, and reasonably well made. There are no rattles or creaks as you hold or insert it into the computer. The body is white in colour and wrapped in a clear plastic case which seems designed both to protect the adaptor and lend it a stylised look. The body also contains a WPS button for push-button pairing using the standard Wi-Fi Protected Setup system. The latest 11ac wireless protocol should excel at range so in order to test this we setup a number of scenarios. All setups used a TP-Link AC1750 router which has three external 5 dBi antennae and so should provide a good signal strength with which to test. The first setup was a test at 1m from the router to test the maximum throughput of the adapter. Then the router was placed in a 5th floor window and the adapter was attached to a laptop 10m from the building (total distance 18m). For the third setup the laptop and adapter were taken 80m from the building (total distance 82m). In all the tests the adaptor was compared against the performance of an early 2011 17in MacBook Pro (Early 2011) with an internal 802.11n card using a 3×3 MIMO antennae setup. Both the 201.11ac and the 802.11n adapter will be using the 5GHz frequency band. In the first close-range test the adapter achieved a speed of 184Mb/s. This is in line with the speeds achieved by the current D-Link and Netgear 802.11ac USB adaptors but a little slower than the 200-209 Mb/s of the Asus adapters. At this distance the 802.11n adapter also reached exactly 184Mb/s. In the second test the W900U reached a speed of 149Mb/s, compared to the 802.11n speed of 67Mb/s. This is also faster than the 125 Mb/s of the D-link DWA-182. In the final test the W900U returned a speed of 143Mb/s, almost twice the 86 Mb/s we acheived from 802.11n. As an additional extreme test, just for fun we took the adaptor 120m from the building. This even introduced an obstruction from trees, losing a clear line of sight. Even so the adapter still managed to return a speed of 11 Mb/s.
