eMMC (embedded multimedia card) provides a boost in read and write performance compared to traditional NAND flash memories, let alone micro SD cards. Samsung has now announced the manufacturing of the first 32, 64, and 128GB embedded memory solution based on Universal Flash Storage (UFS) 2.0 standard delivering up to 350MB/s read speed and 150MB/s write speed, or 40% improvement in read speed over eMMC 5.1.This should help further reduce boot time, and app loading times. Moreover, while eMMC read and write operating are sequential (half-duplex), UFS 2.0 allows for full-duplex operating, meaning writing and reading can happen at the same time.
UFS can achieve this feat thanks to a LVDS (Low-Voltage Differential Signaling) serial interface with dedicated read/write paths contrary to the parallel 8-bit interface used for eMMC. Combined with a Command Queue(CQ), which sorts out the commands that needs to be carried out, UFS 2.0 allows three times faster file copy, and three times the multitasking capability compared to existing solutions. Command Queue is also an improvement found in eMMC 5.1 specifications.
If you are a JEDEC member, you can download UFS 2.0 specification (JESD220B) via JEDEC Universal Flash Storage page.