Who makes the best 802.11ac Wi-Fi client USB adapter?

Buffalo AirStation WI-U2-866D review: Decent performance for a low price

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At a Glance
  • Buffalo Technology AirStation WI-U2-866D

Who makes the best 802.11ac Wi-Fi client USB adapter?

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In our roundup of 802.11ac Wi-Fi client USB adapters, the best performances that Buffalo Technology’s AirStation WI-U2-866D turned in were good enough only for second-place finishes, and the device ended up in fourth place overall. But its $40 street price—$30 less than the cost of the top-performing Asus USB-AC56—renders it an attractive value.

The WI-U2-866D’s industrial design echoes that of Buffalo’s new 802.11ac routers, and it has the same charcoal-gray finish and silver accents. Its antennas are mounted internally. Buffalo doesn’t provide a cradle, but you will find a bendable USB 2.0 stub cable in the box. I didn’t find this accessory to be of much use, since it wasn’t strong enough to prevent the adapter from flopping over.


I like how the hinged USB interface folds into a recess on the back of the adapter to protect it. (Click to zoom.)

The adapter’s hinged interface is much more useful and allows you to position the adapter either vertically or horizontally. The adapter is a little over 3.5 inches long, but it will protrude less than an inch from your computer when it’s vertically oriented (and that’s how I tested it). When you’re not using the adapter, its USB interface folds neatly into a recessed area on the back of the adapter to create a very compact package for travel.

Buffalo’s model was the only adapter in the test group not to have a WPS button, so you’ll need to remember your router’s passphrase to establish a wireless connection. Like Asus, Buffalo provides a software utility that reports connection status, signal strength, and other details. You can use the utility with either Buffalo’s adapter or your laptop’s built-in adapter.

802.11ac Wi-Fi adapters

Buffalo’s adapter took strong second-place finishes at longer distances (look at the dark blue bars). (Click to zoom.) 

Buffalo’s adapter performed much better than most of its competitors when the client was in my home theater (35 feet from the router), delivering TCP throughput of 227 megabits per second. It delivered the second-fastest throughput when the client was in my home office, which is 65 feet from the router. Curiously, the WI-U2-866D was the second-slowest at close range, when the client was only 9 feet from the router. And it was 96 mbps slower than the Asus USB-AC56 when the client was in the kitchen, which is 20 feet from the router.

The WI-U2-866D is a good value, but the absence of a WPS button is a bit of a downer.

Note: This review is part of a roundup of six 802.11ac Wi-Fi client USB adapters. For more, read the introduction to the roundup.

This story, "Buffalo AirStation WI-U2-866D review: Decent performance for a low price" was originally published by TechHive.

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At a Glance
  • If you don’t mind the absence of a WPS button, Buffalo’s low-priced WI-UW-866D 802.11ac Wi-Fi USB adapter is a very good value.


    • Very good performance at long range
    • Hinged USB interface
    • Compact design
    • Low price


    • No WPS button
    • No USB cradle
    • Mediocre close-range performance
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