A USB Wi-Fi adapter is a useful device that can help improve your Wi-Fi connection. These days all laptops, and many desktops, have a wireless adapter integrated via a mini PCIe card, but the wireless adapters that most computers ship with are generally behind the current curve, often by a generation or more. This is where a USB Wi-Fi adapter is useful: to upgrade the wireless networking capability of the laptop with a simple plug-and-play solution.
For this guide, we've collected the latest hardware from several manufacturers and run them through their paces. We test performance using NetPerf software at three distances on both the 2.4 GHz and 5 GHz frequency.
Within the 802.11ac standard, there are many speeds that are supported. They are based on the combined theoretical maximum speed of the 2.4GHz and the 5GHz frequencies, rounded as needed. For example, AC1200 has a 2.4GHz speed of 300Mbps and a 5GHz speed of 867Mbps, which sums to 1167 and gets rounded up to AC1200. Here’s a chart of current speed ratings:
It should be noted that on the fastest standards, AC3200 and AC5300, this is based on total bandwidth sent across three connections: one 2.4GHz and two 5GHz. A single client will never receive that much bandwidth. While this is not a significant limitation, it does amount to a certain amount of manufacturer exaggeration. On an AC5300 router, for example, they state “delivers faster Wi-Fi speeds of up to 5300 Mbps,” but do not make note that it’s only in aggregate, and the fastest clients we could find for testing are AC1900 which top out at less than the theoretical AC1300 speeds.
The latest so-called ‘Wave 2’ routers support MU-MIMO. This stands for multiple user, multiple input, multiple output. While 802.11n MIMO was limited to a single client, MU-MIMO can be used across four simultaneous clients. It takes advantage of the radio wave phenomenon of multipath propagation. By this process, data transmission becomes more efficient as less bandwidth is wasted, and simultaneous transmissions can occur across multiple channels.
The limiting factor is there are few clients that support MU-MIMO at this time. However, on the cutting edge, a few USB Wi-Fi adapters do support it, providing a pathway for upgrading to improved throughput. In our previous testing, MU-MIMO in a client improved throughput by a serious 134% compared to non-MU-MIMO speeds.
While beamforming debuted with the 802.11n standard, it was significantly limited by requiring the router and the client to be from the same manufacturer. With 802.11ac, beamforming is now part of the standard, providing compatibility between different manufacturers.
This technology allows the router to focus the transmission of the data stream more directly to the client, rather than transmitting equally in all directions. This increases the signal strength to where it is needed, with less interference. While this is now a standard, there are still proprietary implementations of beamforming such as Netgear’s Beamforming+ or D-Link’s AC Smartbeam, which promise even faster speeds when both the router and client are both from the same manufacturer.
USB 2.0 vs 3.0
Older adapters interface with the computer via the older USB 2.0 connector. This ubiquitous, but now aging standard has a theoretical maximum throughput of 480 megabits per second (mbps) (equivalent to 60 megabytes per second [Mbps]). This is still plenty quick, but with today’s faster adapters, with a good signal to a high end router, it can turn into a bottleneck to network throughput.
Better to use an adapter with the more current USB 3.0 interface, as most current models do. This faster flavor of USB offers performance of 5 gigabits per second (gbps), which is equal to 640 Mbps. With the faster connector, the networking speeds can be maximized.
Every USB Wi-Fi adapter has an antenna. However, there are many approaches to this essential component. Some adapters have an internal antenna, or even multiple internal antennas, all in a compact form factor. For a stronger signal, size can make the difference, and a larger, external antenna can help increase signal strength. In areas of congestion, a directional antenna can also be useful, while most of these adapters have an omnidirectional antenna that transmits in all directions.
Many adapters print their antennas directly onto the circuit board. This is a simplified approach, that preserves the svelte lines of the adapter. The drawback is that the antennas are vulnerable to electrical interference from other circuitry in proximity on the board. An alternative approach is to have the antenna for the adapter as a foldout to get it away from the electronic interference, but able to become compact for storage and transport.
Various adapters ship with different software packages. Some manufacturers take the barebones approach, with the only software included as the driver for the OS to utilize the adapter. While minimalist in theory, this has its merit as Windows does a pretty good job these days of managing the wireless connections (as opposed to some prior versions of Windows such as XP that were beyond mediocre at this essential task).
The alternative approach is for a USB Wi-Fi adapter to ship with a full software package. While this can bring some additional features, the downside is that in some implementations, this can end up interfering with the integrated wireless settings and become a bloated application that doesn't offer anything more than what Windows can natively do.
USB Wi-Fi adapters come in various form factors of various sizes, each of them more ideal for certain use case scenarios. At the small end of the scale, there are nano adapters. While generally slower, a nano adapter has less protrusion, and is ideal for a smaller notebook doing traveling duty.
Going to the opposite end, there are the large adapters. These would be a hindrance from a portability standpoint with a notebook, but work well with a desktop (or desktop replacement notebook) that needs a wireless connection. They have high gain antennas, and offer the faster wireless standards.
In between, are the standard size adapters, that are roughly the size of a traditional USB flash drive. They balance throughput speed, and signal strength within a reasonably sized package that maintains portability.
In some cases it is all about the accessories. Consider the “Total package” with such extras as a USB extension cable or docking cradle. While these hardly make or break the purchase, it can definitely enhance the usability factor for the wireless adapter.
How we test USB Wi-Fi adapters
Testing was done for throughput using NetPerf software. A desktop with a Gigabit Ethernet port (10/100/1000) is used to send the data via a wired connection to the router. Three test runs were done on each wireless adapter at each of the 2.4 GHz and 5 GHz frequencies, at three distances: close, far and fringe, with the highest throughput of each parameter reported. The router used is the Asus AC1900P, our choice for the Best Budget Gaming Router. The throughput is tested at a “close” 8’ (2.4m) distance with direct line of sight, and also at a “far” 30’ (9.1m) distance with an obstructing floor and wall in the way, as well as some metal ductwork intervening. For this revision, we added tests in a Wi-Fi “fringe” location, that we started using for our Best Wireless Extender Buying Guide, except we did not plug in an extender to make the wireless connection more challenging for the wireless adapter and to test their antennas.
Others we tested
The Asus USB-AC68 adapter features a novel folding design that incorporates dual antennas. It includes a USB 3.0 connection, the AC1900 standard, Asus AiRadar Beamforming, and MU-MIMO via a 3x4 antenna design. The results are a bit of a mixed bag as this Asus adapter lags in the 2.4 GHz tests at both distances. While the 5 GHz tests are stronger, it was still not the fastest at either the close or far distance tested. The Asus USB-AC68 has many positive reviews on Amazon, with a street price of $75.
The D-Link DWA-171, features AC600 speeds, but as it has been on the market since 2013, it does not support Beamforming or MU-MIMO. On throughput testing, the D-Link DWA-171 has solid speeds on the closer distances, particularly on the 2.4 GHz frequency. However, this model had a quite slow throughput on the 2.4 GHz fringe test of just 13.6 Mbps showing the weakness of the older design. The real value of the DWA-171 becomes apparent when we figure in the street price of $19.99, making this model a strong contender for a budget pick.
The D-Link DWA-192 debuted at CES 2015, and was our previous pick for the best overall wireless adapter. It connects to the USB 3.0 port via an extension cable, making this adapter more suited for desktop use, and a stretch to use with a notebook. This D-Link model was the first AC1900 USB Wi-Fi adapter to market. The antennas—a total of three of them—are all internal, so it is less likely to get knocked down on a desk. It also supports beamforming, and Advanced AC SmartBeam, a proprietary version of beamforming to D-Link routers.
Performance of this DWA-192 remains solid when tested on both the 2.4 GHz and 5 GHz wireless frequencies. The 3x3 antenna design showed its merit on the close and far tests, making the D-Link DWA-192 ideal for more challenging wireless connections where the signal strength from the router is weaker. This adapter also excelled with fast throughput speeds on the far 5 GHz frequency test at 210.8 Mbps, which actually beats our Trendnet pick at this distance from the router. While this model was over $100 for months after debut, the price is currently $55 on Amazon, making it still worthy of consideration.
The Edimax EW7822ULC amazingly has AC1200 speeds in a super a small device. On the close range tests, the speeds were also class leading on both frequencies, with a 5 GHz run of 279 Mbps truly impressive for an adapter of any size, let alone this small fry.
There are two issues that keep us from recommending this adapter. The first is that the speeds in the fringe wireless position were quite slow, and on the 2.4 GHz test, it was our slowest throughput measured, and even another Edimax adapter of the same size was literally 10x faster. The second issue is that this adapter got super hot in testing, and no other adapter got anything close to this high temp, which we reproduced in repeat runs. While it is affordable at $19.99, we would rather go with another recommended wireless adapter.
The Trendnet TEW-804UB was a previous bargain pick for a smaller AC600 adapter. Comparing the throughput speeds, it is still respectable, although we did not have a unit for testing on the new fringe wireless tests. It is no longer available as a new product on Amazon, and with newer models available, we recommend buyers look to those.
The Edimax EW-7811Un does have the really compact size going for it, as it barely protrudes from a USB port, and cannot really be made any smaller despite the solitary blue LED. However, the wireless standard it adheres to is N150, so don’t expect it to win any speed races. That being said, in testing, despite its small size, the signal is maintained, and the speeds are at least passable at 51.5 Mbps on the 2.4 GHz close test, and 44.7 Mbps on the far test. Heck, when we threw at it the fringe wireless test wondering if it could really even maintain the wireless connection, it was even passable at 38.8 Mbps despite the tiny antenna configuration. For a basic adapter, at a bargain basement, ramen noodle price, this Edimax fits the bill. Just realize for a little more, most users will be better off with an adapter that offers 5 GHz connectivity.
The Linksys WUSB6300 is a standard size adapter, supporting AC1200 speeds. It proved easy to install, stable in testing, and had no real flaws in use. The issue with this adapter is that it trailed on throughput speeds compared to our other recommended picks. In addition, the $39 street price makes it more expensive than our budget picks for this category.
The Netgear A6210 is another example of how competitive this segment has become. It also features AC1200 speeds, and a flip up antenna. It was stable throughout our testing after an easy install. The street price of $40 makes it quite affordable, but its slower 2.4 GHz speeds across the board, especially in the fringe location keeps it from earning our recommendation.
Upcoming products in the USB Wi-Fi adapter space are expected to have incorporation of MU-MIMO, as well as faster speeds, such as AC1900 and AC2600. Beyond that, look for products that will work with WiGig, the 802.11ad standard that is anticipated to offer speeds of 4 to 7 Gbps utilizing the 60 GHz higher frequency.
As new products and technologies become available, we’ll incorporate them into this guide to help you make an informed purchasing decision.
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