Learn what is the difference between SFF-8639 and SFF-8643

What is the difference between SFF-8639 and SFF-8643

1. SFF-8639 (now called U.2)
The SFF-8639 is the latest connector design for connecting MultiLink SAS drives or PCIe drives (including hard drives and SSD drives). It was recently renamed "U.2" by the SSD Small Tool Group.
SFF-8639 is a revision of SFF-8680, which is a 29-pin 2-lane SAS drive interface. The SFF-8639 U.2 is a 68-pin drive interface connector with higher signal quality that supports 12Gb/s SAS and Gen 3 x4 PCIe or PCI Express NVMe.
The SFF-8639 U.2 connector can be integrated onto a pcb "docking backplane" for multiple drives, or onto a single drive "T-Card" adapter.
The SFF-8639 U.2 connector has a total of 6 high-speed signal paths, but the SAS and PCIe specifications can only use up to 4 lanes at any one time.

2. SFF-8643
The SFF-8643 is the latest HD MiniSAS connector design for implementing HD SAS internal interconnect solutions.
The SFF-8643 is a 36-pin "High Density SAS" connector with a plastic body normally used for internal connections. A typical application is an INTERNAL SAS link between a SAS HBA and a SAS drive.
SFF-8643 complies with the latest SAS 3.0 specification and supports 12Gb/s data transfer protocol.
The HD MiniSAS external counterpart of SFF-8643 is SFF-8644, which is also SAS 3.0 compatible and also supports 12Gb/s SAS data transfer speed.
Both the SFF-8643 and SFF-8644 can support up to 4 ports (4 lanes) of SAS data.