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eMMC vs SSD: Choosing the Right Storage Technology

As a computer hardware professional, I‘m regularly advising clients on the best storage solutions for their needs. Whether it‘s for a laptop, desktop, server or portable device, understanding the key differences between storage technologies is critical. Two of the most common options are eMMC (embedded MultiMediaCard) and SSD (solid state drive) storage. On the surface these seem similar — both utilize NAND flash memory chips rather than mechanical hard disk platters. But under the hood, several important distinctions affect performance, lifespan and total cost of ownership.

In this comprehensive guide, I’ll unpack the technical nitty gritty between eMMC and SSD storage. You’ll learn the history behind these technologies, how they work, where each excels, and how to choose the right one for your use case. I‘ll also speculate on what emerging storage tech like Intel’s Optane may mean for the future. Let‘s dive in!

A Brief History of eMMC and SSD Storage

Solid state storage traces its roots back to the 1950s when magnetic core memory delivered the first taste of non-volatile speeds. This was followed in the 1970s by early integrated circuit based storage using exotic materials like niobium-titanium. But it wasn‘t until the commercialization of NAND flash memory in the late 90s/early 2000s that SSD technology really took off in consumer devices.

The first NAND flash based SSDs were produced by StorageTek in 1991 featuring an SAS interface. This was followed in 1995 by M-Systems “DiskOnChip” which used an IDE interface. Early capacity measurements were in single digit MBs — a far cry from today’s multi-TB offerings! By the late 2000s SSD adoption saw hockey stick growth thanks to precipitous NAND flash price drops. SATA interfaces also reduced bottlenecks, with each generation ratcheting up speeds from 1.5Gbps to 16Gbps currently.

On the embedded storage front, SanDisk and Siemens pioneered the MultiMediaCard (MMC) standard in 1997. Initially targeting digital cameras for storage expansion, the MMC format saw rapid adoption in other mobile devices like PDAs. In 2006 an JEDEC task force released the first Embedded MMC standard (eMMC) which integrated the MMC interface as a small ball grid array chip package onto circuit boards. This delivered an all-in-one storage solution well suited for space constrained mobile applications.

Over the past 15+ years, successive eMMC and SSD generations have built on these foundations — with ever higher speeds, capacities and capabilities. Next let‘s do a technical deep dive on how these technologies actually work.

|| Year || Storage Milestone ||
| 1980s | EEPROM integrated circuit storage |
| 1991 | First NAND Flash SSD by StorageTek |
| 1995 | DiskOnChip IDE flash SSDs |
| 1997 | MultiMediaCard standard |
| 2000s | SATA interface SSD adoption |
| 2006 | First eMMC standard |
| 2010s | PCIe/NVMe interface SSDs |
| 2020s | PCIe 4.0, QLC and Optane SSDs |

Understanding eMMC and SSD Technical Operation

Despite surface appearances, eMMC modules and SSD drives handle the intricacies of data storage quite differently under the hood. Here I‘ll break down the internal architecture and operation of these technologies.

eMMC – Embedded Integrated Storage

As the name indicates, eMMC modules directly integrate NAND flash and a simple controller onto the device‘s PCB via epoxy solder balls underneath a protective metal case. This provides permanent onboard storage that cannot be removed or upgraded. Cost optimization is a critical driver due to adoption in price-sensitive devices like low/mid-range smartphones.

Inside you‘ll find vertically stacked NAND flash ICs that make up the bulk of the surface area. These raw flash "dies" provide the non-volatile storage capacity through arrays of floating gate memory transistors. Each IC die has independent CE#, RE#, WE#, ALE, CLE and I/O signal connections to the controller.

The brains of the operation is a minimalist controller placed alongside or under the NAND dies inside the embedded module. This manages vital functions like:

  • Error correction (ECC) – Detects and fixes corrupted bits
  • Wear leveling – Distributes writes across ICs
  • Bad block mapping – Reroutes data from failed cells
  • Logical block addressing – Presents unified address space
  • Host interface – Communicates using eMMC 5.1 protocol

By combining the flash memory and controller in a single low clearance component, eMMC storage can be compactly integrated into small form factor devices with a minimal PCB footprint. Costs are also kept low by eschewing advanced functionality in the simplified controller hardware.

However, eMMC does suffer capacity, performance and upgrade limitations compared to modular SSD counterparts — as we’ll explore next.

eMMC embedded storage module interior diagram

eMMC modules integrate NAND flash memory and a basic controller via low clearance epoxy solder balls (credit: The SSD Review)

SSD – Modular Flash Storage

Unlike eMMCs, solid state drives are designed from the ground up for easy removability and upgrades via disk drive style enclosures. This modular approach comes in a range of physical sizes with the most popular being the compact 2.5” form factor. External connectivity is provided using high performance SATA, PCI Express or proprietary interfaces.

Peering inside reveals vertically stacked PCBs encompassing potentially 100s of NAND flash integrated circuits. Cost optimizations are less pronounced with focus instead on maximizing storage density. The primary SSD controller is a large multi-channel chip handling advanced storage management functionality including:

  • Write amplification mitigation – Minimizes NAND writes
  • LDPC error correction – Fixes errors in marginal cells
  • Full disk encryption – Secure data protection
  • TRIM/SMART – Enhances responsiveness and monitoring
  • RAID support – Enables drive redundancy/failover
  • End-to-end data integrity – Guarantees against corruption

Supporting the controller is a DDR3/DDR4 DRAM chip providing supplemental caching and buffer space. This is a key advantage over eMMC solutions which lack onboard caching capabilities leading to slower random access speeds. The SSD controller communicates externally through ports like SATA, PCIe or U.2. Many SSDs also allow daisy chaining over multiple lanes to further multiply speeds.

While historically more costly per GB compared to HDDs, SSD prices have reached parity for mid/high capacity storage thanks to technology improvements like QLC NAND. And compared to eMMC, the modular nature of SSD enables regular upgrades as demands increase.

SSD internal layout showing key components

SSDs integrate advanced controller hardware with host connectivity and NAND memory (credit: WD Corporation)

Now that we‘ve covered how these technologies operate, let‘s analyze where each one excels…

Choosing Between eMMC vs SSD Storage

With an understanding of the technical inner workings, we can now compare the relative strengths and weaknesses of embedded versus modular storage solutions. Key factors include:

  • Cost – Impacts affordability in volume devices
  • Capacity – Determines total storage ceiling
  • Speed – Affects real-world loading times
  • Lifespan – Useful life before replacement needed
  • Power – Important for mobile applications
  • Functionality – Advanced features require capable controller

Evaluating where eMMC and SSD diverge across these vectors will demonstrate ideal usage scenarios and limitations. I‘ve compiled high level differences in the following chart:

eMMC 5.1 Storage SATA SSD NVMe SSD
Seq. Read Speed 400 MB/s 550 MB/s 3500+ MB/s
Seq. Write Speed 170 MB/s 520 MB/s 3000+ MB/s
Average IOPS 8000/1000 R/W 100K/88K R/W >700K R/W
Interface eMMC 5.1 SATA III PCIe 3.0/4.0 x4
Cost Per GB $0.20 $0.20 $0.25+
Capacities 64GB max 4TB max 100TB max
DRAM Cache None Up to several GB Up to several GB
Power Consumption Low Moderate Higher
Advanced Features Minimal Full suite Optimized for NVMe
Use Cases Low/mid tablets, Chromebooks, smartphones Gaming PCs, workstations Servers, high perf PCs

Examining the data makes clear that SSDs deliver far better performance and capacities compared to embedded eMMC solutions. Costs are also nearly equal when comparing eMMC to basic SATA drives. However eMMC maintains advantages in physical size and low power operation — making them attractive for compact mobile devices where blazing speed is not critical.

To better understand real-world implications of these tradeoffs, let‘s walk through some detailed use case comparisons.

eMMC in Budget Chromebooks & Tablets

Chromebooks have surged in popularity over the past few years thanks to low cost and simplified operation. Most models rely on eMMC solutions ranging from 32 to 64GB rather than more expensive SSDs. This allows OEMs like Asus, Acer and Lenovo to hit aggressive $199 to $299 retail price points.

Given lightweight ChromeOS storage demands and prevalence of cloud syncing services, the smaller eMMC capacities pose little impediment for the target market. Cost and battery runtime take priority over raw speed. And should storage needs change, high capacity microSD cards can readily expand local content access.

Similarly for low/mid-range Android tablets, eMMC hits the sweet spot balancing functionality, price and power efficiency. While intensive 3D mobile games may benefit from the reduced level loading times of SSDs, most tablet usage like web browsing, video playback and simple apps exhibit adequate performance from eMMC solutions. And again, removable microSD cards enable capacity growth as needed.

Device Storage Type Benefits Limitations
Asus C223 Chromebook 64GB eMMC Low cost, compact, 10hr battery Lower speed than SSD, not upgradeable
Amazon Fire HD 8 Tablet 32GB eMMC Affordable, 17hr video playback Mediocre benchmark performance

SSDs Accelerate Gaming PCs & Workstations

At the other end of the spectrum lie bleeding edge gaming rigs and professional content creation workstations. In these devices, storage speed plays an enormous role dictating real-world productivity and user experience. Top tier NMVe SSDs using the PCI Express interface now saturate a blazing fast 16 Gbps across x4 lanes.

For competitive multiplayer titles, this translates to map and texture assets loading in a few seconds rather than half a minute or longer on rotational drives. The high queue depth and random IOPS performance of leading edge drives like Samsung’s 980 Pro minimizes texture pop-in and lag during matches when every millisecond counts. LOAD accelerator tech further optimizes data location across multiple NAND dies to minimize access latency.

Similarly video editors working with high resolution 8K RED or ARRI footage need storage that keeps pace with massive file sizes. A headset like the Seagate FireCuda 510 hits consistent 2.9GB/sec speeds ideal for smooth scrubbing and timeline editing. And compared to pokey HDDs, SSDs simplify project collaboration by accelerating render previews, export times and uploading for review.

While bleeding edge SSDs still demand premium prices compared to TB HDDs, the responsiveness and productivity gains outweigh the cost for many power users. Compared to more pedestrian SATA or eMMC solutions, NVMe SSDs remove storage bottlenecks to fully exploit expensive CPUs, GPUs, displays and peripherals alike.

Device Storage Type Benefits Limitations
Gaming Desktop 500GB WD Black SN850 7000 MB/s load times Costs 5-10X more per GB than HDD
Video Editing Workstation 2TB Samsung 980 Pro Fast syncing/transfer of 8K footage Limited endurance writes before replacement

Emerging Storage Technologies

As embedded and SSD storage rapidly evolve, even faster and more capacious technologies sit just over the horizon. Two key developments I’m tracking with excitement are Intel’s Optane Memory and Storage Class Memory (SCM).

Intel Optane utilizes an entirely new approach dubbed 3D Xpoint conceived jointly with Micron. This stacks flash cells vertically across multiple layers to achieve breakthrough densities and access times. Rather than storing a binary 0 or 1, Xpoint cells exhibit variable resistance readable at gradients inbetween — boosting capacities and endurance.

Optane can be deployed as a caching layer to accelerate HDDs or as an SSD replacement boasting 1000X lower latency and vastly higher endurance than NAND flash. Products like the Optane 905P have already proven compelling for demanding workloads despite high costs — achieving up to 575K random read IOPS! As manufacturing scales, expect Optane SSD pricing to become increasingly competitive versus traditional NAND.

Storage Class Memory (SCM) is an umbrella term for various high speed, non-volatile memory technologies. The goal is providing near-DRAM access latency at higher bit densities by integrating right onto DDR memory busses. Intel and Micron’s 3D XPoint is considered a type of SCM, as are MRAM and ReRAM alternatives currently under development.

By combining the speed of RAM with the persistence of SSDs, SCM aims delivering the best of both worlds. Latency could improve from ~50-100us for NVMe SSDs down to sub 10us — opening new horizons for datacentric computing. If pricing ultimately matches DRAM, the lines between memory and storage will further blur in exciting ways!

While SCM remains confined to research, proof of concepts like Viking Technology’s cube highlight the promise. Their prototype SCM device achieved latency down to 5 nanonseconds while saturating DDR4 bandwidth. As volumes scale in coming years, next generation memory technologies could displace traditional NAND flash. I‘ll be following developments closely here with measured optimism!

Conclusion — Finding the Right Storage Fit

Deciding between integrated eMMC versus modular SSD storage involves juggling priorities around cost, speed and use case fit. For permanently embedded operation in space/power constrained mobile devices, eMMC strikes an effective balance — providing adequate real-world performance despite limitations around capacity and upgradeability.

Meanwhile SSDs carrying higher BOM costs excel in desktops, workstations and enterprise environments where continually optimizing storage speed enhances productivity and operations. Form factors range from compact 2.5” SATA to hyper-fast add-in cards, while caching algorithms and advanced controllers extract every last drop of performance from the underlying NAND flash memory cells.

Looking ahead, innovative alternatives like 3D XPoint and speculative Storage Class Memory promise accelerating gains in speed and density. But proven and mature storage mediums have inertia on their side — it took over two decades for SSDs to displace venerable mechanical hard drives in client computing applications. Still, I’ll be eagerly benchmarking these emerging solutions here as viable challengers to both SSD and eMMC dominance!

What questions on eMMC versus SSD still remain? Feel free to post in the comments section below.