Time for the test. In total we tested eighteen different PCI-Express SSDs. While they can have the form of M.2-devices as well as PCI-Express x4 insertion cards, all of them have at least a PCI-Express 3.0 x4 interface. This means that the bandwidth should not be a hindrance in order to achieve the 4 GB/s. With the exception of a single model, they all use the NVMe-protocol.
The latest models, including the Samsung 960 Evo and Pro, are of course included. However, as reference we also included the older models in this test. Because of this you can clearly see in what regards we saw progress over the last years.