NEXT-GEN SSDS ON TEST

Forget those old 2.5-inchers — Josh Collins explores the shiny new M.2 and PCIe-card SSDs to find out what’s hot and what’s not.

Forget those old 2.5-inchers — we explore the shiny new M.2 and PCIe-card SSDs to find out what’s hot and what’s not.

The Next Generation Form Factor (NGFF) SSD standard has provided a development platform for newer, faster and smaller PC storage devices, featuring a new physical interface and support for multiple communication protocols. What’s emerged as the dominant solution during this development is the 22mm-wide M.2 form factor, typically ranging in lengths from 30mm through to 110mm, depending on capacity. For example, a ‘2280’ M.2 drive — the most common standard size for M.2 drives — uses a 22mmwide connection interface with a PCB length of 80mm.

NGFF drives can actually handle multiple communication protocols, with SATA 6Gbps, USB 3.0 and PCI-Express (PCIe) all technically supported. Different module keying — configs of the gold connectors that are used to plug devices in — is used to differentiate between the various interface and protocol offerings. For this roundup, we saw two types of keying. The first was the M-key type, used by devices that feature PCIe x4 support, while the second was the M+B-key type, which incorporates both an M-key and B-key. The latter devices are able to communicate via protocols based on PCIe or SATA 6Gbps.

In this feature, we’ve primarily focused on M.2 drives based on the 2280 form factor, with 22mm-wide connection interfaces and PCBs reaching 80mm in length — unit thicknesses varies widely, often depending on drive capacity. The tested units are further split into two core communication protocols: SATA 6Gbps and NVMe (aka ‘Non-Volatile Memory express’ standard).

Another derivative of the NGFF category is the SFF-8639 interface that was renamed U.2, post launch. M.2 and U.2 present the same connectivity bandwidth and both can reach their maximum bandwidth performance through use of four PCI-Express lanes. The M.2, U.2 and PCIe slot (PCIe x4) interfaces are all inter-operable due to using the same communication protocol, allowing for potential NVMe RAID solutions that run across M.2, U.2 and PCIe add-in-card interfaces. We’ve included Intel 750 series and HyperX Predator PCIe slot NVMe SSDs in the roundup for comparison. The PCIe x4 logical device interface provides a 32Gbps link, while SATA 6Gbps (obviously) provides a 6Gbps communication link.