Asus USB-AC56 review

Ever look at the latest MacBook models with envy, and wish you could get a taste of 11ac Wi-Fi, the new higher-speed wireless networking technology? Then await good news – not only does Asus’ USB wireless adaptor break sprint and long-distance records compared to older 802.11n networking, it also does all this on the Mac. And does so rather well, as the USB-AC56 Dual-band Wireless-AC1200 USB 3.0 Wi-Fi Adapter ticks the boxes to actually deliver a worthwhile upgrade.

First, it connects to a computer by USB 3.0, even if that does narrow the Apple Mac choice somewhat to mid-2012 and later models. If you have an earlier Mac with Thunderbolt but now USB 3.0 (early 20122 to mid 2012), consider a Thunderbolt dock such as the Belkin Thunderbolt Express Dock. But the high-bandwidth USB 3.0 data port – when combined with two internal, one external antennae and a two-stream wireless chipset – means that truly 11n-busting speeds are now readily attainable from an aftermarket Wi-Fi adaptor.

Asus USB-AC56: Build and design

It may superficially resemble a modern USB thumbdrive, but the Asus USB-AC56 is not a compact accessory. It arrives as a tough black plastic obelisk 115 mm long, its rectangular mass tapering slightly at both ends, and it’s decorated with oddly faceted sides. Along the matt underside these resemble the oblique cleave lines of a stealth bomber; on the fancy shiny top are regular diamond-like patterns cut into the gloss plastic.

Each end has an identical endcap – the left side covers the male USB plug, the right a screw-fitting connector to attach an optional aerial that’s included in the box.

Asus USB-AC56 USB end

Asus USB-AC56 SMA end

You can insert just the USB-AC56 device into a Mac without its additional aerial, where it will protrude a substantial 100 mm. It’s not a pretty sight, and is ill-suited to safe handling – for the sake of busted USB ports we’d recommend you don’t carry your laptop around far at home or in the office with the dongle in place.

The gantry situation is made worse with the screw-on aerial attached, particularly if you don’t bend the hinge 90 degrees to point the antenna skywards. The combined length of dongle plus twig can become a very pendulous 245 mm.

Fortunately there is a smart solution, also included in the kit, in the form of a USB extension cable with cradle to hold the whole dongle-plus-aerial assembly. In our tests, we also found data performance was marginally improved with the device sited just remote of the test MacBook.

Asus USB-AC56 with cradle

Asus provides drivers for Windows XP to 8, Linux, and OS X for the Realtek RTL8812AU chipset inside. In the case of OS X, an installer package will install the necessary Realtek kernel extension (kext) and the Wireless-AC Network on your computer.

Instead of OS X’s built-in wireless software, usually accessed from System Preferences/Network, you use the supplied application to find available wireless networks and connect with necessary security passwords.

The app is simple and plain-looking, showing just SSID names, channels, encryption type and BSSID codes. Missing is any useful dBm information for RSSI signal strength, noise levels or available 802.11 protocols, and there’s no indication of current wireless sync speed. You can at least save configuration for more than one wireless network under the Profiles tab.

Asus USB-AC56: How we test

We tested the Asus USB-AC56 on a MacBook Pro (15-inch, Retina, Late 2013), a model also well equipped with its own built-in 3x3 MIMO draft-11ac wireless capability. For a wireless router we used the current Apple AirPort Extreme (6th Generation) launched in June 2013.

Data measurements were made with a Mac mini (Late 2012) as server, with both computers running WiFiPerf 1.6. Most tests were run over a fixed 2 minute timespan. To simulate better real-world data transfers, the application was set to measure TCP rather than UDP traffic. And since send and receive data-transmission modes can give different results, we made measurements both client to server (MacBook to Mac mini) and vice versa.

We tested at three different ranges: 1 m and 2 m, to try to gauge best available speeds; and a medium/long-range test at 10 m, through one intervening 6in (150 mm) plaster/wood stud wall.

Asus USB-AC56: Performance

Configured for 802.11ac operation, the client-to-server result at 1 m was very good when compared to typical 11n systems, at 275 Mb/s. But that figure paled next to the steady 480 Mb/s result when the data flow was reversed.

At 2 m, performance for StC traffic caught up somewhat, now averaging 405 Mb/s, while CtS transfers reached the Asus adaptor’s best figures – 490 Mb/s.

By comparison, the MacBook’s built-in 11ac chipset showed its best performance at 1 m, measured client to server, where it achieved an average speed of 600 Mb/s over a 2 min test period.

Asus USB-AC56 performance 11ac 2m

In our tests using WiFiPerf the Asus USB-AC56 could comfortably deliver wireless speeds exceeding 480 Mb/s at 2 m range

The longer-range 11ac test at 10 m also returned excellent results, considering the distance and added obstruction. Server to client, the USB-AC56 averaged 295 Mb/s and in the other direction it nearly maintained 400 Mb/s, its average just below at 398 Mb/s.

For use with legacy wireless access points, we also ran tests of 11n performance of the Asus USB-AC56. Best results were found at 2 m, server to client, with around 119 Mb/s; or 96 Mb/s when reversed.

At 10 m range and through the stud wall, 11n performance results remained remarkably good. These averaged 94 and 113 MB/s, from and to the dongle respectively.

Considering that the USB-AC56 is designed to work with two rather than the three available MIMO wireless streams – thus potentially enabling a maximum 802.11ac sync speed of 867 Mb/s (2 x 433.3 Mb/s) – these were all impressive results.

To support the synthetic tests and help verify that there were no significant errors in test setup we also ran real-world file-transfer tests at 2 m using 11ac protocol. Here we simply copied a 5 GB MPEG-4 file between computers, using OS X 10.9 Maverick’s now-default SMB2 file sharing protocol. The indicated network speed reported by Activity was in line with previous results, fluctuating between around 50 and 70 MB/s (350–560 Mb/s).


The Asus USB-AC56 is an effective upgrade that can bring faster wireless networking to the Apple Mac. You’ll need a USB 3.0 port for best results, but under the right conditions you may get close to half-gigabit wireless transfers at short range, and the benefit of increased performance at longer ranges too. It’s not pretty but if you need the speed this Asus adaptor comes highly recommended.

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