M.2 pci connected SSD's are a good 3x faster than SATA connected SSD's.
400-500 MB/s read/write speeds in the average SATA SSD.
1200-1500 MB/s in the M.2
If someone was claiming increased CPU interrupts from an M.2 vs. a SATA connection, something else was the root cause!
Mac Pro 8x3.33GHz i7, 16GB, 256GB SSD(OS, apps), 3x2TB 7200 HD(data); MacBook Pro 2.8GHz, 6GB, 128GB SSD HD(OS, apps), 750GB 7200 HD(data); 2xTrue Precision 8; Apogee AD-16; 2xMOTU 828mk3, Evolution UC-33e; Faderport; WiRanger, iPad & the analog mixer has retired