What is U.2?
Formerly known as SFF-8639, is an interface standard defined by SSD Form Factor Work Group.
It was developed for the enterprise market and designed to be used with new PCI Express drives along with SAS and SATA drives. It uses up to four PCI Express lanes and two SATA lanes.
U.2 connector supports NVMe standard protocol and PCI-E 3.0×4 bus, which makes the U.2 SSD have a theoretical bandwidth up to 32Gbps and have advantages of high speed, low latency, and low power consumption.
Currently, HGST Ultrastar SN100, OCZ Z-Drive 6000 and other enterprise-class SSDs have a common feature, that is, they provide two form specifications. One is the traditional PCI-E expansion card model, and the other is the 2.5 inch U.2 interface disk style.
In November 2015, Intel introduced the 750 series SSD which is available in both PCI Express and U.2 variants.
However, the U.2 SSD that can be bought by ordinary consumers includes the Intel 750 series, which includes three capacity specifications: 400 GB, 800 GB, and 1.2 TB.
The sequential reading and writing speed of the Intel 750 U.2 SSD of 1.2TB capacity can be up to 2400 MB/s and 1200 MB/s, respectively. As for its random reading and writing speed, this SSD can reach 440000 IOPS and 290,000 IOPS, respectively. In a word, the performance is very strong. If you want to know the explanation to terminologies about disk performance, please read the recommended article.
In addition, ASUS, Gigabyte, MSI, ASRock, and other vendors have announced support for U.2, and demonstrated the new U.2 data line and U.2-M.2 converter. At present, the ASUS ROG Maximus VIII Extreme motherboard has been equipped with a U.2 interface.
U.2 devices may be connected to an M.2 port using an adapter.
U.2 compared with M.2
- U.2 allows hot-swap, whereas M.2 does not.
- U.2 can use 3.3 V or 12 V for power, while M.2 only supports 3.3 V.