Apple’s OS X Yosemite 10.10.3 update brings support for NVM Express (NVMe), a new faster interface for solid state drives.
AHCI (Advanced Host Controller Interface) dates back to 2004 and was designed with hard drives in mind. While that doesn’t rule out SSDs, AHCI is more optimized for high latency rotating media than low latency non-volatile storage. As a result AHCI can’t take full advantage of SSDs and since the future is in non-volatile storage (like NAND and MRAM), the industry had to develop a software interface that abolishes the limits of AHCI.
The result is NVMe, short for Non-Volatile Memory Express. It was developed by an industry consortium with over 80 members and the development was directed by giants like Intel, Samsung, and LSI. NVMe is built specifically for SSDs and PCIe and as software interfaces usually live for at least a decade before being replaced.
The biggest advantage of NVMe is its low latency of 2.8 µs compared to 6.0 µs for AHCI. Thanks to the lower latency, disk usage time will decrease, your computer will spend more time at idle, and thus your battery life will be increased. In addition, there could be some situations where NVMe’s better queue support helps with performance.
NVMe is designed to meet the industry’s needs as we move to future memory technologies. Apple’s first device to support the technology is the new 12-inch Retina MacBook. It’s likely that future Apple devices will take advantage of NVMe’s performance as well.