Not only are powerline networking adapters getting faster, but they are also getting smaller. Netgear's latest offering, the XAVB5101 Powerline Nano500 Set, consists of a pair of its latest - and smallest - XAV5101 adapters. These comply with the HomePlug AV (200Mbps) standard, but use a wider radio spectrum to increase the speed to 500Mbps. They are backwards-compatible with standard 200Mbps HomePlug AV products and they can also co-exist happily on the same network with the original Homeplug 1.0 (85Mbps) devices, although they can't interoperate with them.
As consumers tire of poor Wi-Fi performance in congested neighbourhoods, but continue to need a reliable solution for connecting TVs and set-top boxes to their home networks, the demand for powerline adapters is increasing. These offer a simple plug-and-play method of networking, and as long as the mains wiring is in reasonable condition it can outperform many Wi-Fi connections. The XAV5101 adapters have a single Gigabit Ethernet LAN port.
Of course, as with any networking technology, the headline figure of 500Mbps doesn't tell the whole story. This figure is simply the physical layer (PHY) link rate, and doesn't take into account protocol overheads. The best real-world performance we've seen from powerline adapters is just under 100Mbps from Netgear's XAVB5001 adapter, which is the bigger brother of the XAV5101 and utilises the same Atheros AR7400 chip. This chip uses a frequency range of 2-68MHz to achieve the higher speeds (the standard HomePlug AV range is 2-28MHz).
In practice, we found that the XAVB5101 set delivers the best performance figures we've seen from a HomePlug device. With the two adapters on the same extension lead, we measured speeds using Totusoft's LAN Speed Test of 117Mbps (write) and 128Mbps (read), a 20 per cent improvement over the XAV5001, which is probably down to firmware improvements. For a more realistic idea of performance in an electrically noisy environment, we plugged the adapters in random sockets and extension leads around the house, and easily managed speeds of around 60Mbps. We also paired one adapter with a 200Mbps Homeplug AV adapter (on the extension lead) and saw speeds of around 60-70Mbps.
These well-built adapters are the smallest we've seen to date, and are no wider than a standard UK mains plug. This makes it easy to plug them into a double wall socket. There are two short network cables provided in the box, but there's no software included. However, Netgear's excellent free powerline utility (for Windows or Mac) can be downloaded from the website. This enables you to view the link speeds, rename the adapters, configure quality of service (QoS) parameters for networked clients, and also turn off the three status LEDs if they annoy you. A separate free utility is available for updating the adapter firmware.
HomePlug devices are still not particularly cheap, but they are convenient and are getting smaller and faster. The Netgear XAVB5101 set is one of the smallest and fastest we've seen.
Pros: Great performance; well-made; small size makes them ideal for tight spaces.
Cons: No software supplied, although free download is available; quite expensive.