Design and features
Unlike many bland Homeplug adapters, at least the PA551 has a touch of style, with a distinctive black body and white fascia panel. The passthrough mains socket is at the top of the fascia, with three green/orange status lights below. The build quality is excellent, with a solid feel to the adapters. In the box is the quick installation guide, mini-CD with the software utility and manual, plus two Ethernet cables.
Unlike the AV500 Nano adapters, the PA551 has a Gigabit Ethernet port, which gives them a decent - but not massive - performance advantage. The adapters are pretty bulky, though, being the same width but longer than the previous AV200 version (PA251). They won't fit side-by-side in a ganged extension socket, which in some ways is no bad thing - using them in extension sockets is never a good idea as it can affect performance if the extension has a surge suppressor.
The small Powerline utility is quite basic, but tells you links speeds and allows QoS settings to be changed, either using simple application settings (Internet, Games, Audio/Video or VoIP), or more complex VLAN or TOS bits.
|Quite stylish for a Homeplug adapter|
|The utility lets you set QoS parameters and upgrade firmware|
I used my standard test setup (see this post for more details), and used the latest version (1.3) of Totusoft's LAN Speed Test, with LST Server on the remote PC to check the throughput. The adapters pair up very quickly when plugged in - something that some adapters seem to take ages to do. Using the default packet size of 1MB and 100 test iterations, the results stack up pretty well compared to other AV500 adapters I've tested.
Average write speeds were 124Mbps, and read speeds 125Mbps, which is about the same as other AV500 models I've seen. It also means that the Gigabit Ethernet ports do give a 25% improvement over the AV500 Nano adapters, which are limited to 100Mbps. Out of interest, I also ran tests with a pair of older PA251 AV200 adapters - these managed around 70Mbps read and write throughput.
So you do get a lot of benefit out of moving to the AV500 standard, but you should never expect full 500Mbps speeds - that only refers to the PHY link speed, not throughput. According to the software utility, link speeds were around 350Mbps on the PA551 during testing - they wouldn't connect any higher. Variability during test runs wasn't too bad, either, at around 5-10%.
At a street price of around £80, the PA551 twin-pack is cheaper than the Devolo dLAN 500 AVPlus and speeds are comparable. They do look more attractive than most other models, but they are large. The passthrough mains socket is ideal for those with a limited number of wall sockets, though. This product should definitely be on your shortlist if you're looking for some reasonably-priced, well-made Homeplug adapters.
Model: TP-Link TL-PA551KIT AV500+ Gigabit Powerline Adapter
Contact : TP-Link
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