The number of
SATA 3 connectors provided on the controller board.
Initially, the SATA standard was developed for connecting internal drives, primarily hard drives (HDDs). And SATA 3 is the most modern and fastest version of this interface: it provides data transfer rates up to 600 MB / s (4.8 Gbps). For hard drives, this is quite enough, but for faster SSD modules, this is not enough. So although PCI controllers with such an interface can still be found on the market, there are very few of them. The number of SATA 3 connectors depends on the type of controller (see above): in expansion cards there can be only one such port, but in RAID modules there are at least 2, and more often 4.
The number of
M.2 connectors provided on the controller board.
This interface actually combines the capabilities of PCI Express 3.0, SATA3 (see above) and USB 3.0. Due to this, it can be used both for connecting drives (primarily SSD modules in a miniature form factor) and for expansion cards. The specific purpose and capabilities of the M.2 connector in different controller models may be different, these points should be clarified according to the manufacturer's documentation.
