eMMC vs SSD

eMMC vs SSD: Six Must-Know Facts

• Only a few companies handle global SSD production: SanDisk, SK Hynix, Seagate Technology, Western Digital Corp, Crucial, Intel, Kingston Technology, Micron Technology Inc., and Samsung
• The type of NAND technology an SSD uses determines its lifespan.
• Manufacturers can combine SSD technology with fixed-disk magnetic storage to produce a hybrid hard drive (HHD)
• eMMC storage within portable devices can be combined with SD and microSD cards.
• Like SSDs, eMMCs combine flash storage and an integrated circuit controller. 
• Applications for eMMCs are rapidly diversifying and include robotics, automotive, networking, medical devices, and IoT. 

The type of memory a device uses is key to its speed and performance. When choosing devices like laptops or smartphones, the device specifications often include a range of memory technologies that have different implications for your user experience. 

Two key types of storage used in contemporary computing are eMMC and SSD storage. While you may often find SSD drives in premium devices, eMMC is a common storage type in cheaper laptops. Its ‌reliable speed and performance make it popular with manufacturers. 

Knowing the difference between these two storage types and the technologies behind them can help you select a laptop, computer, or portable device that will meet your needs. In this article, we share the similarities and differences of eMMC vs SSD and the pros and cons of these leading technologies. 

What is eMMC?

eMMC stands for embedded MultiMediaCard, a type of internal storage used in a wide range of electronic devices. Unlike similar forms of multimedia storage like Secure Digital (SD) cards, USB drives, and solid-state drives (SSD), an eMMC cannot be removed because it is embedded in a device. eMMC storage is the primary form of storage in devices like smartphones, and tablets. Manufacturers are also increasingly using eMMC as the primary form of storage for cheaper laptops like Chromebooks. 

The MultiMediaCard standard

eMMC storage is designed and operates in accordance with the MultiMediaCard standard. SanDisk and Siemens (founders of the MultiMediaCard Association) developed this standard in the 1990s. It is available as an open standard for device manufacturers who want to include this technology in their products. Since its first release in 1997, there have been multiple versions and types of this standard including MMC-Plus, MMC-Mobile, and eMMC. The eMMC standard was developed in 2006 by JEDEC. The latest eMMC standard is eMMC standard, JESD84-B51, which was released by JEDEC in January 2019. It can achieve speeds that are comparable to SATA-based SSDs, 400 Mbps.

Structure of an eMMC card 

eMMC (embedded MMC) cards simply contain flash memory and basic controller hardware and firmware that performs error correction and data management. The components within the card are arranged in a small ball grid array (BGA). The BGA is based on an 8-bit parallel interface and has 100, 153, and 169 ball packages. Device manufacturers can then embed this module on a printed circuit board like a motherboard, as its non-volatile storage system.

NAND flash memory

eMMC data storage uses NAND flash memory. This is a type of non-volatile storage technology that is not reliant on the maintenance of a power supply to store data. Data is stored in blocks using electrical circuits within the module. The semiconductors involved are known as floating gate transistors (FGT) and provide extra charge to memory cells to maintain the charge in the absence of a power supply. 

eMMC applications 

eMMC modules are embedded permanently in portable devices, cellphones, and Internet of Things (IoT) sensors and actuators. The devices use the eMMC to read and write data to individual logical block addresses with the eMMC. The card is not user removable and the eMMC cannot be upgraded which has implications for the overall performance and speed a device can achieve.  

What is SSD?

Solid state drives, shortened to SSD are a type of non-volatile storage device that is used for the persistent storage of data, irrespective of the presence of a power supply. Since their development in the late 1970s, they have grown in sophistication and adoption to become the leading type of storage technology in computers, largely replacing traditional hard disk drives (HDDs).

SSD supersedes the hard disk drive

SSD technology is faster than the original hard drive technology that used a spinning disk with read/write head on an arm. NAND flash memory replaces the physical and mechanical writing and rewriting of memory in an SSD, which produces a significant uptick in load times and performance. The solid-state drive is not vulnerable to mechanical breakdown with jolts or blows to the laptop or computer. 

The structure and function of a solid state drive

SSDs feature a complex of interconnected flash memory chips where the SSD reads and writes its data and handles sequential or random data requests. The flash memory chips are made of silicone and stacked in grids to a range of densities. 

Within the chips, floating gate transistors (FGTs) retain the electrical charge that holds memory. Data that are held in charged cells or blocks have a designation of 1, whereas cells with no electrical charge carry a 0. SSDs write to empty blocks in a process known as a program/erase cycle (P/E cycle). Each SSD has a limited number of P/E cycles so over time the memory capacity of these drives becomes degraded (slowing the device) until they cannot store further information. 

Types of memory in SSDs 

SSDs use several types of memory that store data in different ways. The types of memory used by an SSD determine its performance and price.

• Single-level cells (SLCs): the fastest and most resilient form of memory with each cell holding a single bit of data at a time (1 or 0). 
• Multi-level cells (MLCs): each cell in an MMC holds two bits of data in each cell. This doubles the amount of storage space in the SSD, but increases write speed.
• Triple-level cells (TLCs): hold three times the data of an SLC. However, write speeds are slow and TLC SSDs are less durable than other memory types. 

Use of SSDs

Manufacturers use SSDs technology for hard drives in computers, servers, and portable devices like smartphones. SSDs are also used in graphics cards. The compactness, speed, and utility of graphics cards make them suitable for high specification applications that require low latency memory access. SSDs can achieve this level of speed because they can read directly from the data they store.

eMMC vs SSD: Side-by-Side Comparison

The Differences Between eMMC vs SSD

• eMMC and SSD are both non-volatile memory storage types that use NAND flash technology but significant differences do exist. 
• A key difference is that eMMC is embedded and cannot be removed and upgraded, but an SSD hard drive can be replaced or upgraded according to user requirements. 
• eMMCs are soldered onto the motherboard as an integral component. Unlike eMMCs, SSDs have a flash memory controller that connects the memory to the computer motherboard via the SATA interface. 
• SSD speeds eclipse those of eMMC. SSDs have read-write speeds exceeding 1500 Mbps, but eMMC has a specified top speed of only 400 Mbps. 
• The amount of storage each technology can provide also differs. eMMC cards are available with memory capacity ranging from 32GB up to 128GB. To add additional storage capacity, eMMCs are used alongside cloud storage. SSD has a much larger capacity, starting at 128GB to multiterabyte storage. 
• Adoption of SSD technology is continually increasing but it remains significantly more expensive than eMMC. Because of the significant cost difference, laptop manufacturers use eMMCs for memory storage.

eMMC

SSD

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