While it's not possible to carry out conclusive performance testing on VPN services due to the wide range of factors that can affect the speeds users see, we carry out speed tests to get a feel for how each service performs. We test all services using their clients' default settings unless changes are required for connection stability.
Tests before 2021: We ran tests from a London-based connection that typically saw un-VPN'd speeds of over 59MB/s (472Mbit/s). We test multiple servers from each provider in three locations: the UK, the Netherlands and the USA and retest any anomalous results.
Tests after 2021: Tests are run via a private business connection with a full-speed 1 Gbit/s symmetric fibre connection.
Our core tests include large file downloads via HTTP (and FTP, prior to 2020) but note that these figures can only ever be a snapshot of performance at a single point in time, rather than being fully representative. We refer back to prior test results where relevant. Tests are carried out on a Windows 10 PC with Windows Defender enabled. We download reference files via HTTP from public servers around the world using curl at the command line. Prior to 2020 FTP download speeds were measured using Filezilla, while early HTTP download tests were carried out in Chrome and measured using the Chrono Download Manager extension.
While UK and Dutch endpoints can, from the best VPN services, match the speed of many internet connections without a VPN, connection speeds to the USA are typically far slower due to the distances involved. However, it's notable that a number of VPN services, notably those with extensive network infrastructure, can produce faster speeds to the US than a non-VPN'd counterpart.
Depending on client requirements, we may also test whether we're able to view region-locked streaming video content from various streaming services, which have included Netflix, Crunchyroll and Shudder in the US, and All 4, Channel 5, and BBC iPlayer in the UK, among others. Most of these services seek to identify and block IP addresses associated with VPN endpoints, so what works one month may not the next. Most streaming services have their updated terms and conditions in recent years to to indicate that region-shifting of this kind is not allowed.