Until recently, desktop computers often do not come with built-in Wi-Fi. Users can install a Wi-Fi add-on card. Or they can connect a USB Wi-Fi dongle, like the Asus USB-AC68 Dual-Band AC1900 USB 3.0 Wi-Fi Adapter.

For me, the Wi-Fi dongle is the more appealing option, because there is no need to open up the PC chassis. Pre-built computers, especially, may not support an add-on card.

The Asus USB-AC68 supports the latest 802.11ac Wi-Fi standard, up to a maximum speed of 1,300Mbps. This theoretical throughput is equal to that offered by a standard Wi-Fi card.

This dongle is not just for desktop PCs. It is also useful for older laptops that lack support for the 802.11ac standard. On paper, the AC68's top speed is also higher than the 867Mbps speed of the Wi-Fi adapters typically found in laptops.

Asus has put some thought into the design. The AC68 resembles a large USB flash drive. Simply unfurl its two antennas when using the dongle.

You can either plug the AC68 directly into the computer's USB 3.0 port or use the included desktop cradle that keeps the AC68 in an upright fashion. Because the cradle is attached via a cable (around 80cm long) to the computer's USB port, you can better position the Wi-Fi adapter for the best Wi-Fi reception.

Installation is not quite as simple as just plugging in the Wi-Fi dongle to the USB port. You have to install the software driver as the dongle does not appear to be supported natively in Windows 10.

To test the AC68, I attached it to a laptop and measured the download speed from another laptop connected to a router via Ethernet cable. The AC68 managed an average download speed of 480Mbps, which is slightly faster than the 411Mbps with the laptop's integrated Wi-Fi adapter.

Vincent Chang

•Verdict: Useful accessory for devices that lack Wi-Fi, but the performance gain over an integrated Wi-Fi adapter was marginal.