What is the difference between the PCIE interface and the U2 interface except for the connection form of the SSD of the same specification?

What is the difference between the PCIE interface and the U2 interface except for the connection form of the SSD of the same specification?

1.There is no difference.

2.Simply because the U.2 solid state requirement is small.

3.The performance is exactly the same.

1>Physical form factor: AIC (PCIe card), 2.5 inches (SFF-8639 interface or SATA interface)

2>Electrical Standard: PCIe, SAS, SATA (subset of SAS)

3>Data Protocol: NVMe, AHCI

(In principle, U.2 is equal to SFF-8639. For the convenience of understanding, the following refers to the U.2 interface using the PCIe bus)

It should be noted that the two solid-state forms of the PCIe bus (based on the NVMe protocol), AIC and 2.5-inch U.2, which is the solid state of the SFF-8639 interface, are exactly the same in terms of electrical standards and data protocols.

The U.2 solid state drive is usually connected to the desktop through the SFF-6543 interface (same physical shape as the Mini SAS). Originally, the connection cable is relatively cheap, but the price of U.2 solid state drive will increase when more people use it.

Rack servers need NVMe HBA card and backplane to use U.2 solid state (existing SAS HBA cards cannot support PCIe+NVMe solid state). There are two interfaces: SFF-8643 and Oculink. The general server does not have this requirement, and the PCIe plug-in solid state does not have so many problems, just plug it directly into the riser.

It should be noted that the 2.5-inch U.2 solid state is not necessarily applicable to the scene where AIC solid state is applicable, because even if the latter is installed on the riser card, the height exceeds the height of the HHHL card. The solution of replacing the NVMe HBA card and backplane is not cost-effective in the case of deploying a small number of NVMe solid-state.

Let's talk about SFF-8639 and SFF-8643, the former is the interface of SAS and U.2 hard disk, the latter is the interface of SAS and U.2 controller (ie Mini SAS), and the data cable of the latter is universal (although The pin definitions are different, and upgrading to PCIe U.2 solid state must replace the HBA card and backplane at the same time).

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