The M.2 NVMe SSD originally started as an M.2 SATA SSD, which is used to describe the smallest form factor of an SSD that can be packed into the size of a gum stick. The reason why M.2  SSDs have become more favorable in recent times in taking over SATA SSDs is due to the simple installation and cableless drive. Typically, SATA SSDs provide a transfer speed of up to 6Gb/s, meanwhile the NVMe drives offer up to 64Gb/s. The M.2 NVMe drives are much quicker due to them utilizing flash memory modules which allows quick start-ups, reliability, and increased performance.

The U.2 (2.5”) NVMe SSD or otherwise formerly known as the SFF-8639, is a high-performance drive with transfer speed up to 64Gb/s. U.2 drives are not commonly found (although slowly becoming more common today) because it was first designed for the specialized markets of large-scale enterprises. Although the U.2 drives are pricey and difficult to come by, they were essential for these businesses as their threshold for performance and were needed for the intensive applications.

Both M.2 and U.2 drives utilize the PCIe protocol that is commonly found to connect hardware devices to a computer. They both utilize flash memory and the same PCIe bus interface of x4. This means that both drives interfaces allow for the max transfer speeds of 64Gb/s.

Although both drives utilize the same PCIe connection they are vastly different in terms of size and connection types. The U.2 NVMe drive appears almost like a 2.5” drive and it connects to to a specific connector (SFF-8639) that some motherboards may include. On the other hand, M.2 SATA or NVMe drive are much smaller and connect to motherboard M.2 slots, which can save more space and reduce cabling.  

At Icy Dock we’d like to offer versatile equipment for a variety of solutions. Introducing interchangeable trays of the ToughArmor MB601TP-1B (MB601M2K-1B) and MB601TP-B (MB601VK-1B). These two trays are interchangeable within a single enclosure (MB601VK-1B or MB601M2K-1B). If you are already using either one of the enclosure, you can simply purchase the MB601TP-B tray for the U.2 NVMe drive or MB601TP-1B for the M.2 NVMe drive.

If you need a quick way to access data from your NVMe drive, the EZ-Adapter MB931U-1VB allows connection to the MB601TP-B tray,  MB601TP-1B tray or bare U.2 NVMe drive through USB with transfer rate up to 10Gbps.