Editor’s note: This roundup of powerline ethernet adapters is continually updated. It was originally published on January 15, 2015, and this is the third update. Since the number of products in the story was becoming unwieldy, we’ve removed the older models and kept only the latest HomePlug AV2 MIMO and ITU G.hn adapters. If you want to see the story as it was originally published in January 2015, click here.

This latest iteration adds an entirely new review of the ZyXEL PLA5456KIT to our earlier reviews of the D-Link DHP-701AV, Extollo LANsocket 1500, TP-Link TL-PA8030P KIT, and the Trendnet TPL-420E2K. You’ll also find the one ITU G.hn adapter we’ve reviewed to date: the Comtrend PG-9172.

The lay of the land

The powerline networking landscape continues its rapid evolution with a couple of new groundbreaking products based on the state-of-the-art HomePlug AV2 MIMO standard. The ZyXEL PLA5456 has achieved parity with the previous fastest adapter we’ve tested—the Extollo LANSocket 1500—while the TP-Link TL-PA8030P remains the only kit we’ve tested to boast three ethernet ports (ZyXEL’s kit has two).

The new wave of products also highlights two tiers of HomePlug AV2 MIMO performance: The three adapters we’ve tested that are based on Broadcom chips—D-Link’s DHP-701AV, Extollo’s LANSocket 1500, and ZyXel’s PLA5456—are significantly faster than the competition that’s based on Qualcomm chips (these being the only two companies shipping AV2 MIMO chips in the U.S. at this writing). We have no way of evaluating claims by the two companies as to why Broadcom-based adapters perform faster.

Benchmarks and prices of the top performers.

In my previous testing I looked at a couple of other HomePlug AV2 MIMO products as well as a Comtrend kit that was the first retail product based on a competing, less familiar powerline standard called G.hn.

HomePlug and G.hn both define a method for carrying data—including audio and video—over standard electrical cables. This enables you to use existing wires in your home as a data network. HomePlug is based on the IEEE 1901 standard, while G.hn is based on the competing ITU G.9960 standard.

In addition to using power lines to form a network, G.hn also supports using telephone wiring and coaxial cables. The IEEE also has a standard to facilitate hybrid networks, IEEE 1905.1. It’s backed primarily by the HomePlug Alliance, which runs a 1905.1 certification program for powerline, Wi-Fi, and coax-based products under the trade name nVoy. Because 1905.1 operates using software, an amended version, 1905.1a, adds support for other network technologies, including G.hn. But no one is operating a certification program for 1905.1a at this point, and as a practical matter, HomePlug and G.hn products simply don’t work together.

Both G.hn and the latest version of HomePlug—HomePlug AV2 MIMO—use a variant of the multiple input/multiple output technology you’ll find in 802.11n and 802.11ac network devices. Using MIMO, a powerline device will utilize all three wires in an electrical cable, transmitting data on any two pairs: Line/Neutral, Line/Ground, Neutral/Ground, and so on to achieve theoretical TCP throughput of up to 1.2Gbps. Earlier HomePlug devices transmit using only the Line and Neutral wires; SISO (Single Input, Single Output) HomePlug AV delivered maximum throughput of 600Mbps.

HomePlug AV2 MIMO

This illustration provided by the HomePlug Alliance shows how MIMO works when applied to powerline networking.

You should be aware that real-world performance is considerably lower in both cases. Also, your home must have three-prong outlets to get the full benefit from MIMO. HomePlug AV2 MIMO adapters will work with two-prong outlets, but they’ll fall back to SISO mode (single input/single output) and deliver less throughput.

This illustration provided by the HomePlug Alliance shows how MIMO works when applied to powerline networking.

No mixing: HomePlug and G.hn are incompatible

Powerline networking can be faster and more reliable than Wi-Fi when you need to serve client devices that are behind very thick walls—particularly concrete or masonry—or that are multiple stories away from your router. But the two powerline standards discussed here are not interoperable, so choose one or the other.

To create a powerline network, plug one adapter an AC outlet near your router and connect it to your router using an ethernet cable. Plug other adapters into AC outlets near the devices you want to add to the network, and then connect those devices to the adapters using ethernet cables. Don’t plug the adapters into outlet strips or surge protectors, as those devices might consider the data packets traveling over the wire to be noise and filter them out.

Powerline ethernet adapters

In our experience, powerline performance varies widely depending on the location of the adapters. Each product was much slower when the adapter connected to the router was further away from the adapter attached to the client, although their performance relative to each other didn’t change.

While the HomePlug Alliance certifies powerline products bearing the HomePlug brand as interoperable, that doesn’t mean you’ll get optimal performance from a network formed by a mix of HomePlug AV2 MIMO brands. When I connected D-Link’s DHP-701AV adapter to my router and connected the client computer to Netgear’s PL1200-100PAS, I saw significantly degraded performance compared to using the same brand at both ends. Interestingly enough, I saw much better performance in the reverse scenario: The Netgear connected to the router and the D-Link on the client end. Bottom line: No matter which powerline product you choose, stick with one standard and one brand.

You might also want to read this how-to guide that will help you get the best performance from your powerline network: Pump up your powerline.

You can mix powerline and Wi-Fi devices, though, and most people do. You can also buy powerline-based Wi-Fi range extenders that create local wireless access points in rooms where your Wi-Fi signal can’t reach. Powerline is a fantastic solution when Wi-Fi alone doesn’t cut it, but Wi-Fi is much more convenient if for no other reason than Wi-Fi adapters are built into nearly every device (smartphones, laptops, tablets, media streamers). Plus, there’s the whole “no wires” thing; heck, even newer set-top boxes and DVRs have gone wireless.

So which powerline device is fastest?

It’s notable that HomePlug AV2 MIMO adapters dominate this roundup, with Extollo’s LANsocket 1500, ZyXel’s PLA5456, and D-Link’s DHP-701AV in a virtual tie, with ZyXel’s PLA5405 finishing fourth. The only G.hn adapter in the roundup, Comtrend’s PG-9172, placed fifth.

Unless you’re on a very tight budget, avoid older and cheaper powerline adapters. Their performance pales in comparison to the newer products. If your home has a limited number of electrical outlets, you might want to buy an adapter that has a power passthrough, even if you end up sacrificing a little performance in the process.

As for the standards battle, it wouldn’t be fair to declare a winner based on the performance of the only G.hn adapter I’ve tested; namely, Comtrend’s PG-9172. Having said that, the PG-9172 is less expensive than all the other adapters, and it was significatnly faster than Netgear’s PLP1200 and TP-Link’s TL-PA8030P.

You can read the individual reviews for details as to how each powerline adapter performed. Just use the story navigation tools below to work your way through each one, or find the product you’re interested in reading about and click on its name from the list below.

This story, "The essential guide to powerline ethernet adapters (including 7 hands-on reviews)" was originally published by TechHive .