eMMCStorage vs UFS Storage:

By Technology

Technology	Benefits	Densities	Configurations	Supply Voltages
3D NAND	Highest NAND capacities Highest read/write bandwidth and I/O speeds Reduced power consumption in standby mode	256Gb–6Tb	x8	1.2V, 1.8V
TLC NAND	Higher density in the same space, at a lower cost than SLC or MLC NAND	64Gb–128Gb	x8	3.3V
MLC NAND	Solid performance and endurance Twice the density of SLC NAND at a lower cost-per-bit Compatibility with the ONFI synchronous interface	16Gb–1Tb	x8	3.3V
SLC NAND	Up to 100,000 P/E cycle endurance Faster throughput than other MLC and TLC NAND technologies Compatible with the ONFI synchronous interface	128Mb–512Gb	x1, x8, x16	1.8V, 3.0V, 3.3V

eMMC Storage Vs UFS Storage! Which One You Prefer And Why?    8GB? 16GB? 32GB? 64GB? 128GB?!! We just can’t seem to get enough. With better cameras and displays – which mean more selfies, bigger pictures and more videos – memory has been a growing priority when consumers shop for new mobile and tablet devices. The Companies are working vigorously to provide solutions to equip users with the ability to store as many images, videos and other media, as well as the capability to multitask on the device without jeopardizing the integrity of basic functionality is imperative. Typically, smartphone and tablets including teh Device of Xiaomi have been using eMMCs (embedded multi-media cards) to store information. But With The announcement of Mi 5 Xiaomi used the embedded memory solution based on Universal Flash Storage (UFS) 2.0 standard and Thus Xiaomi Mi5 become Xiaomi's First Device to come with the UFS memory. Lets have a small info about the both Memory types: eMMC Storage: eMMC, or embedded multimedia card, is an advanced, managed NAND flash memory for mobile applications and still is the dominant go-to memory solution for many consumer electronics, including tablets, smartphones, GPS systems, eReaders, and other mobile computing devices. (“Managed” here means that it’s a solution consisting not only of NAND flash memory, but also controller/interface circuits to help sort out processes and improve performance.) eMMC memory is extremely compact, typically smaller than a postage stamp, allowing for smaller and thinner devices.eMMC memory allows  a smooth pathway to elegant and advanced mobile designs . The latest standard, eMMC 5.1, even furthered the performance and power efficiency. UFS Storage: UFS is the future of Flash memory. UFS 2.0, the most advanced JEDEC standard, offers sequential read/write speeds fast enough to rival SSDs while combining it with the low power consumption of eMMC. With highly intelligent controller and firmware that provide the highest level of performance and quality, users will now have access to a better overall user experience. Along with faster booting, the next generation of flash storage offers a faster data input/output response, three times faster file copy, and three times the multitasking capability. To the average user, this means watching high-quality videos, playing high bandwidth games and other entertainment, along with running multiple applications, and downloading or uploading files, all without interruption in functionality. eMMCStorage vs UFS Storage: UFS boasts a substantial improvement in performance. There are two main factors that contribute to this. UFS has a LVDS(Low-Voltage Differential Signaling) serial interface which has separately dedicated read/write paths. This allows full duplex(two-way interaction) – in other words UFS can read and write simultaneously. eMMC, on the other hand, has a parallel interface which can only send data in one direction at a time – it can either read or write, not at the same time. UFS has a Command Queue(CQ), which sorts out the commands that needs to be carried out. Thus, multiple commands can be addressed at the same time and the order of tasks can be changed accordingly. eMMC, without CQ***, needs to wait for a process to be completed before moving on to the next one. UFS 2.0 solution have a sequential read speed, sequential write speed, random read speed and random write speed each 1.40, 1.66, 2.71, 1.07 times faster, respectively, than eMMC 5.1.

Ref: http://en.miui.com/thread-237786-1-1.html

Ref: https://www.micron.com/products/nand-flash

NAND flash memory

NAND flash memory is a type of nonvolatile storage technology that does not require power to retain data.

An important goal of NAND flash development has been to reduce the cost per bit and to increase maximum chip capacity so that flash memory can compete with magnetic storage devices, such as hard disks. NAND flash has found a market in devices to which large files are frequently uploaded and replaced. MP3 players, digital cameras and USB flash drives use NAND technology.

DOWNLOAD THIS FREE GUIDE

PDF: The NAND flash essentials one-stop shop

Look no further than this guide for your NAND flash memory essentials. Your copy includes an in-depth breakdown of SLC, MLC and TLC NAND, a performance and cost comparison of NAND vs. DRAM and NOR, and how the NAND flash shortage affects SSD supply and pricing. NAND has a finite number of write cycles. NAND failure is usually gradual, as individual cells fail and overall performance degrades, a concept known as wear-out. To help compensate, some vendors overprovision their systems by including more memory than is actually claimed.

When a NAND card wears out, the user simply buys a new one, and the device continues to function. By passing the expense of additional storage on to the consumer, manufacturers have been able to lower the price of consumer electronic devices significantly. New developments in NAND flash memory technology are making the chips smaller, increasing the maximum read-write cycles and lowering voltage demands.

NAND flash can only support a small number of write cycles per block. It delivers speedy read access, but it's not as fast as static read-only memory (ROM) or random access memory (RAM). The technology is shock resistant and can withstand high and low temperatures, as well as submersion in water, so it performs better than hard disks in mobile devices.

NAND flash vs. NOR flash

The two main kinds of flash are NAND and NOR flash memory, which get their names from their respective logic gates.

NAND flash memory is written and read in blocks that are smaller than the device, whereas NOR flash memory reads and writes bytes independently. Use cases for both NOR and NAND flash memory include laptop and desktop computers; digital cameras and audio players; smartphones; video games; and scientific, industrial and medical electronics.

NAND flash offers faster erase and write times than NOR flash, while NAND technology delivers better density at a lower cost per bit. NAND also offers up to ten times the endurance or NOR.

NAND isn't a suitable replacement for ROM because it doesn't deliver byte-level random access, which data stored on ROM usually requires. NOR memory makes a good replacement for RAM and ROM drives; NAND is more closely related to secondary storage devices, such as hard disks. This makes it good for mass storage use cases.

NAND flash shortage

A NAND flash shortage began in 2016. The shortage is partially the result of demand, but it is also because vendors are transitioning from manufacturing 2D or planar NAND to much denser 3D NAND technology. Planar NAND has only one layer of memory cells, whereas 3D NAND stacks cells on top of one another. Samsung refers to 3D NAND as Vertical NAND or V-NAND. 

Ref: http://searchstorage.techtarget.com/definition/NAND-flash-memory