M.2 is a new form of connectivity for SSD drives that allows them to connect directly to the PCI-E bus rather than going through a SATA controller. By bypassing the SATA controller a M.2 drive can have a theoretical maximum throughput as high as 2GB/s which is over three times faster than the 600MB/s SATA is limited to! Unfortunately, temperature and motherboard compatibility is a major issue with these M.2 drives.
