First and for most, mabilis naman po lahat ng SSDs compared to the traditional HDD na mechanical pins ang gamit to read and write data. The oldest ones are SATA drives are often connected to the motherboard using SATA cables, they may provide higher storage/capacity but mas mababa drastically yung speed compared to m.2 or nvme which is directly insreted in a PCIe slot, The SATA hardwares are not limited for their speed sa mismong hardware nila, rather sa type of connection na SATA III. And now for M.2, it is actually a form factor, which means pwedeng maging either SATA pa rin sya or NVMe, and for NVMe which means Non-Volatile Memory Express, which provides data transfer upto 7,000 MB/s para sa mga top of the line brands like Samsung EVO 970, 980. whereas M.2 SSDs can go more or less 600MB/s transfer speed. So at a great margin, mas mabilis po ang M.2 NVMe na SSD.