Have you ever wondered why the latest Galaxy flagships no longer support microSD cards, even though expandable storage was once a defining feature of Android phones? Many gadget enthusiasts feel conflicted when choosing between raw performance and flexible storage, especially as smartphones become more powerful and more expensive.

In this article, you will discover how Samsung’s Galaxy lineup reflects a deeper shift in mobile storage philosophy, driven by breakthroughs in UFS technology, changes in Android’s system design, and the rising importance of on-device AI. By understanding these factors, you will be able to judge whether expandable storage still makes sense in 2026.

You will also learn how cost, real-world performance data, and alternative solutions like cloud storage and external SSDs affect everyday usage. By the end, you will gain a clear framework to choose the right Galaxy device and storage strategy that truly matches your digital lifestyle.

The End of an Era: How Smartphone Storage Priorities Are Changing

The smartphone industry is quietly reaching the end of an era, and storage is at the center of this shift. For many years, expandable storage symbolized freedom and control for users, especially within the Android ecosystem. However, priorities are now changing as performance consistency and system reliability are increasingly valued over raw flexibility.

According to Samsung Semiconductor and Google’s Android engineering documentation, modern smartphones are no longer designed around interchangeable storage components. **The rise of ultra-fast internal storage such as UFS 4.0 has fundamentally redefined what “usable storage” means** in daily smartphone experiences, from app launches to AI-driven features.

Aspect Legacy Priority Current Priority
User expectation Expandable capacity Guaranteed performance
Storage role App + media mix System-critical component
Design focus Flexibility Stability and speed

This transition is not driven by marketing alone. Engineers have repeatedly pointed out that heterogeneous storage environments introduce unpredictable latency and power behavior. Google’s Android team has acknowledged that modern OS architectures assume high random-access performance, something removable media cannot consistently provide. As a result, storage is now treated as part of the core computing stack rather than an accessory.

At the same time, user behavior has evolved. Streaming services, cloud synchronization, and AI-assisted photo management reduce the need for manual file handling. Industry analysts cited by CNET note that flagship users increasingly prefer devices that “just work” without configuration. **The convenience of uniform speed is now seen as more valuable than the option to expand later**.

This does not mean that expandable storage has suddenly become obsolete. Instead, its role has narrowed. External memory is gradually repositioned as archival space rather than an active workspace. From a design perspective, this allows manufacturers to optimize battery life, thermal performance, and water resistance while delivering predictable results to every user.

In this sense, the disappearance of expandable storage from high-end smartphones represents not a loss, but a reordering of priorities. Storage is no longer about how much you can add, but how seamlessly it supports everything you do. That change marks the true end of an era.

Samsung’s Galaxy Lineup and the Hidden Logic Behind Storage Decisions

Samsung’s Galaxy Lineup and the Hidden Logic Behind Storage Decisions のイメージ

Samsung’s Galaxy lineup reveals a carefully tiered logic when it comes to storage decisions, and this structure is far more deliberate than it may appear at first glance. Rather than treating storage as a uniform specification, Samsung aligns internal capacity and microSD support with how each user segment actually interacts with its device. This approach reflects a mix of engineering constraints, user experience control, and long-term ecosystem strategy.

At the top of the hierarchy sit the Galaxy S series models, which have excluded microSD card slots since the Galaxy S21 generation. **This is not simply a cost-saving measure, but a conscious attempt to eliminate performance variability.** According to Samsung Semiconductor documentation, flagship devices rely on UFS 4.0 internal storage capable of multi-gigabyte-per-second throughput and extremely low latency. Introducing external cards with inconsistent speeds would undermine the predictability required for features such as 8K video recording, high-frame-rate burst photography, and on-device AI processing.

From Samsung’s perspective, every Galaxy S user should experience the device exactly as designed, regardless of how tech-savvy they are. Analysts at outlets such as CNET have repeatedly pointed out that microSD cards, even high-end ones, vary widely in sustained write performance. That variance can translate into dropped frames or app instability, outcomes that flagship buyers are least willing to tolerate.

Galaxy Segment microSD Support Primary Storage Philosophy
Galaxy S Series No Maximum speed and system stability
Galaxy Z Series No Space efficiency and advanced form factors
Galaxy A Series Yes Cost efficiency and flexible capacity

The Galaxy Z foldable series follows a similar no-slot policy, but for slightly different reasons. Foldable phones already struggle with extreme internal space constraints due to hinge mechanisms and layered displays. **Every cubic millimeter saved contributes directly to durability and battery size**, both of which remain critical concerns for foldables. Market research cited by Samsung partners also suggests that early adopters of foldable devices are more comfortable with cloud storage and streaming, reducing reliance on removable media.

In contrast, the Galaxy A series embraces microSD expansion as a core value proposition. These devices target users who prioritize practicality and long-term ownership over bleeding-edge performance. In Japan in particular, many A-series buyers reuse existing microSD cards filled with photos, videos, and music accumulated over years. Simply moving the card to a new phone eliminates the friction of data migration, a benefit frequently highlighted by local reviewers and retailers.

Economic logic further reinforces this divide. Internal storage upgrades on flagship models carry a significant premium, a phenomenon often discussed by industry commentators analyzing component sourcing and board-level integration costs. Meanwhile, reputable microSD cards offer dramatically lower cost per gigabyte. **For midrange users who mainly store media rather than run heavy applications, external storage remains the most rational option.**

Seen as a whole, Samsung’s storage strategy resembles a hidden social contract with its users. Flagship buyers trade expandability for guaranteed speed, thermal stability, and a tightly controlled experience. Midrange buyers, on the other hand, gain flexibility and affordability at the expense of absolute performance. This segmentation allows Samsung to optimize each Galaxy tier without forcing a one-size-fits-all solution, ensuring that storage decisions feel intentional rather than arbitrary.

Flagship Models and the Pursuit of Consistent Peak Performance

In flagship smartphones, consistent peak performance is not defined by short bursts of benchmark scores, but by how reliably the device can sustain its maximum capabilities in real-world use. Samsung’s Galaxy S series has been engineered around this principle, and its storage strategy plays a central role in ensuring that performance remains stable under heavy, prolonged workloads.

By eliminating the microSD card slot, Samsung is effectively removing a major source of performance variability. According to specifications published by Samsung Semiconductor, UFS 4.0 delivers sequential read speeds of up to 4,200 MB/s and random read performance around 500,000 IOPS. This level of throughput allows the system to maintain smooth operation even during demanding scenarios such as 8K video recording, high-frame-rate gaming, and on-device AI inference.

From a system design perspective, this decision aligns with research and analysis frequently cited by industry observers at organizations such as IEEE and by storage vendors like Micron and Kioxia. They emphasize that heterogeneous storage environments introduce latency spikes and unpredictable I/O behavior. In a flagship device positioned as a technological reference, such inconsistency is considered unacceptable.

Metric UFS 4.0 (Internal) Typical microSD (UHS-I)
Sequential Read Up to 4,200 MB/s ~90 MB/s
Random Read (IOPS) ~500,000 ~4,000
Power Efficiency Optimized for mobile SoC Relatively inefficient

This performance gap directly affects user experience. When a flagship phone records high-resolution video or processes generative AI tasks locally, the storage subsystem must keep pace with the CPU, GPU, and NPU without triggering buffering delays or thermal throttling. Samsung’s approach ensures that every Galaxy S device behaves within a tightly controlled performance envelope.

Thermal stability is another critical factor. Studies referenced in Samsung’s UFS white papers indicate that integrated UFS storage operates at lower voltages than SD-based solutions, reducing heat generation during sustained transfers. In a compact, sealed chassis designed to meet IP68 standards, minimizing internal heat sources contributes directly to maintaining peak performance over time.

For enthusiasts and power users, this philosophy may appear restrictive at first glance. However, the intent is not to limit choice, but to guarantee that the flagship experience remains uncompromised. By standardizing on ultra-fast internal storage, Samsung is prioritizing predictable, repeatable peak performance, a hallmark expected from devices that define the upper tier of the smartphone market.

Midrange Galaxy Phones and the Ongoing Role of microSD Cards

Midrange Galaxy Phones and the Ongoing Role of microSD Cards のイメージ

In Samsung’s midrange Galaxy lineup, microSD cards continue to play a practical and clearly defined role, and this choice reflects a realistic understanding of how these devices are actually used. Models such as the Galaxy A55 5G are designed for users who prioritize affordability, longevity, and data volume over absolute performance, and microSD expansion fits that philosophy extremely well.

According to Samsung’s official product documentation and Android storage guidelines, midrange devices typically ship with 128GB or 256GB of internal storage. While sufficient for apps and system data, this capacity can quickly be consumed by photos, videos, and offline media. **A microSD card allows users to separate “active” system storage from “passive” media storage**, reducing pressure on internal memory without compromising everyday responsiveness.

Usage Type Internal Storage (UFS) microSD Card
Apps & OS High speed, stable Not recommended
Photos & Videos Fast access Cost‑efficient archive

Research shared by Android Developers shows that, since Scoped Storage became standard, external cards are effectively treated as isolated media containers. This limitation aligns well with midrange usage patterns, where users store large personal libraries but rarely demand sustained high I/O performance. **For this audience, microSD cards function as reliable, low-cost “cold storage” rather than performance-critical components**, a distinction that justifies their continued presence in Galaxy A series phones.

In other words, microSD support in midrange Galaxy phones is not a relic of the past but a deliberate design decision. It offers tangible economic and practical benefits while respecting the technical boundaries imposed by modern Android architecture.

UFS 4.0 Explained: Speed, Latency, and Why It Outclasses microSD

When people ask why UFS 4.0 makes microSD feel obsolete, the answer is not a single benchmark but the combination of speed, latency, and consistency that directly shapes everyday smartphone behavior. **UFS 4.0 is not just faster storage; it is a system-level component designed to keep up with modern mobile computing demands.**

According to specifications published by Samsung Semiconductor and Micron, UFS 4.0 reaches up to around 4,200 MB/s in sequential read and roughly 2,800 MB/s in sequential write. In contrast, the vast majority of microSD cards used in smartphones are limited by the UHS-I interface, which tops out at about 100 MB/s in real-world use. This gap alone explains why high-bitrate 8K video recording or large game installs behave smoothly on internal storage but can stutter or fail on removable media.

Metric UFS 4.0 microSD (UHS-I)
Sequential Read Up to ~4,200 MB/s ~90–100 MB/s
Random Read (IOPS) ~500,000 ~4,000 (A2 class)
Latency Very low, SSD-class High and inconsistent

However, sequential speed is only part of the story. What users actually feel when launching apps or switching tasks is random access performance. Android constantly reads and writes thousands of tiny files, and here **UFS 4.0 outclasses even high-end A2-rated microSD cards by well over two orders of magnitude**. Storage analysts and Android engineers have long pointed out that low IOPS is the main reason apps placed on SD cards feel sluggish, regardless of advertised peak speeds.

Latency also matters. UFS uses a full-duplex, command-queued architecture similar to NVMe SSDs, allowing multiple operations to be processed simultaneously. microSD relies on a far simpler protocol with higher command overhead, which translates into pauses that are short individually but noticeable when multiplied across daily interactions.

Power efficiency further tilts the balance. Samsung’s technical white papers show that UFS operates at significantly lower signaling voltages than SD cards, delivering more data per watt transferred. **Less energy per operation means less heat, fewer slowdowns, and more stable performance during sustained tasks like video capture or AI inference.** In a tightly packed smartphone chassis, this advantage is not theoretical but practical.

For these reasons, UFS 4.0 is not merely a faster alternative to microSD. It is a fundamentally different class of storage, engineered to remove I/O as a bottleneck. Once workloads include real-time AI processing, high-frame-rate imaging, and console-scale games, removable cards designed decades ago simply cannot compete.

Why Random Access Performance Matters More Than Raw Transfer Speed

When storage performance is discussed, headline numbers like “4,000 MB/s read speed” often steal the spotlight. However, in real smartphone usage, random access performance matters far more than raw transfer speed. This is because everyday interactions such as launching apps, switching tasks, checking notifications, or applying AI-powered photo edits rely on thousands of tiny, unpredictable read and write operations rather than long, continuous data streams.

According to Samsung Semiconductor and Micron technical disclosures, modern UFS 4.0 storage achieves random read performance in the range of several hundred thousand IOPS. In contrast, even high-end microSD cards certified under the A2 standard guarantee only a few thousand IOPS at best. This gap is not incremental but exponential, and it directly translates into how “snappy” or “laggy” a device feels in the hand.

Storage Type Typical Random Read IOPS User Experience Impact
UFS 4.0 (Internal) ~500,000 Instant app launch, smooth multitasking
microSD (A2) ~4,000 Delays, stutter during app loading

This difference explains why Android itself has moved away from treating external storage as a place to run apps. Google’s Android engineering team has repeatedly emphasized that low and inconsistent random I/O degrades system stability, increasing the risk of freezes or crashes. As a result, manufacturers like Samsung restrict microSD usage to media storage, keeping the operating system and applications exclusively on fast internal flash.

A concrete example can be seen in camera performance. Capturing a burst of high-resolution photos or recording 8K video generates metadata, thumbnails, and AI processing files in parallel. If random write latency spikes, the camera buffer stalls, leading to dropped frames or missed shots. With UFS storage, these small writes are absorbed instantly, preserving both speed and reliability.

Ultimately, raw transfer speed is like highway top speed, impressive on paper but rarely used. Random access performance is city driving, where responsiveness at every intersection defines the experience. This is why flagship smartphones prioritize ultra-fast internal storage, even at the cost of expandable options, to ensure consistent, premium usability in every tap and swipe.

Android’s Evolving Architecture and the Isolation of External Storage

Android’s relationship with external storage has changed fundamentally over the past decade, and this shift is rooted less in hardware politics than in operating system architecture. As Android evolved from a flexible file-centric OS into a security- and performance-driven platform, external storage was gradually isolated by design. This change directly reshaped how microSD cards are treated on modern Galaxy devices.

Google formally accelerated this transition with the introduction of Scoped Storage, enforced from Android 11 onward. According to the Android Developers documentation, this model sandboxes app data so that each application can only access its own files and limited shared media collections. This architectural decision was made to reduce data leakage, malicious scanning of personal files, and accidental corruption caused by poorly optimized apps.

From an OS perspective, external storage is now considered an untrusted environment. Unlike internal UFS storage, which is tightly integrated with file-based encryption and verified boot, microSD cards can be removed, duplicated, or accessed by other devices. This fundamentally conflicts with Android’s modern security assumptions.

In today’s Android architecture, external storage is no longer part of the core execution environment but a quarantined space for user-managed data.

This distinction becomes clearer when we compare how Android treats internal and external storage at the system level.

Aspect Internal UFS Storage External microSD Storage
Encryption Mandatory, hardware-backed Optional, removable media
App execution Fully supported Restricted or unsupported
Access control System-managed User-mediated permissions

Because of this gap, features once popular with Android enthusiasts, such as moving apps to SD cards or adopting external storage as internal memory, became liabilities rather than advantages. Samsung explicitly disables Adoptable Storage on Galaxy devices, a policy explained in its official support documentation as a measure to prevent instability, data loss, and inconsistent performance.

Researchers and platform engineers have repeatedly pointed out that low and unpredictable IOPS on removable media can stall background services, delay notifications, and even cause ANR errors. In an ecosystem where AI features, real-time translation, and on-device image generation depend on fast and deterministic storage access, this risk is no longer acceptable.

As a result, microSD cards have been repositioned as cold storage for media files rather than an extension of the system itself. This is not a temporary limitation but a structural outcome of Android’s architectural maturity, where reliability, security, and predictable performance now outweigh the flexibility that once defined the platform.

Cost Reality Check: Internal Storage vs microSD vs Cloud Solutions

When choosing a Galaxy device, storage is not just a spec sheet detail but a long-term financial commitment that directly affects usability and peace of mind.

From an economic perspective, internal storage, microSD cards, and cloud solutions each represent very different cost structures.

Understanding these differences is essential before deciding where to allocate your budget.

Internal storage upgrades are the most expensive option upfront, but they deliver guaranteed performance.

In the Japanese market, moving from 256GB to 512GB on a flagship Galaxy typically adds around 15,000 to 20,000 yen.

This translates to roughly 70 yen per additional gigabyte, a figure supported by retail pricing analyses reported by outlets such as CNET.

That price premium reflects not only capacity but also the cost of UFS 4.0 chips, which Samsung Semiconductor positions as comparable to PC-class NVMe SSDs in speed and latency.

For users relying on 8K video capture or on-device AI processing, this cost buys consistency and stability.

There are no hidden bottlenecks, no compatibility questions, and no performance penalties.

Storage Option Typical Cost Effective Cost per GB
Internal UFS Upgrade +15,000–20,000 yen for 256GB About 70 yen
microSD Card 7,000–10,000 yen for 512GB About 14 yen
Cloud Storage 1,300 yen per month (2TB) Ongoing subscription

microSD cards remain unmatched in terms of raw cost efficiency.

A high-quality 512GB microSD card from established brands such as SanDisk often costs less than half of a single internal storage upgrade.

According to long-term pricing trends tracked by major electronics retailers in Japan, the yen-per-gigabyte ratio of microSD continues to decline.

This makes microSD especially attractive for media-heavy users storing music libraries, offline videos, or large photo archives.

However, the lower price comes with trade-offs that are not financial.

Performance limitations, app restrictions imposed by Android, and higher failure rates over time all represent indirect costs.

Cloud storage shifts the cost model from ownership to subscription.

Google One’s 2TB plan costs around 13,000 yen per year, meaning nearly 40,000 yen over three years.

Analyses published by Google and independent consumer tech researchers emphasize that cloud storage excels in redundancy and device-agnostic access.

Yet this model assumes stable connectivity and tolerance for recurring fees.

In Japan, where concerns about data caps and network congestion remain common, downloading large 4K videos can introduce additional, less visible costs.

Over time, cloud storage can easily exceed the one-time expense of physical media.

The real cost difference is not only money, but control.

Internal storage offers speed and predictability, microSD delivers capacity at minimal upfront cost, and cloud services provide resilience at the expense of ongoing payments.

As storage demands continue to grow with AI features and higher-resolution content, these trade-offs become more pronounced.

Choosing wisely means aligning your spending with how and where your data actually lives.

New Workflows: External SSDs and the Rise of USB-C Storage

As microSD slots disappear from flagship smartphones, a new workflow has quietly become mainstream: using external SSDs over USB‑C storage. This shift is not merely a workaround but a structurally superior solution aligned with how modern mobile devices handle data‑intensive tasks. Thanks to USB‑C becoming a universal interface, smartphones, tablets, and laptops now share a common high‑bandwidth storage pathway.

USB‑C external SSDs routinely deliver around 1,000 MB/s in real‑world transfers when using USB 3.2 Gen 2, which is an order of magnitude faster than typical UHS‑I microSD cards. According to Samsung Semiconductor and independent storage benchmarks cited by CNET and Embedded.com, this speed is sufficient for seamless 4K and even 8K video offloading without dropped frames.

Storage Type Typical Speed Primary Use Case
microSD (UHS‑I) 90 MB/s Cold media storage
USB‑C External SSD 800–1,000 MB/s Backup, video workflows
Internal UFS 4.0 4,000+ MB/s Apps, OS, AI processing

This performance gap has real workflow implications. Content creators increasingly shoot directly to internal storage, then offload footage to rugged external SSDs like the Samsung T7 Shield at the end of the day. Samsung itself promotes this use pattern, emphasizing durability features such as IP65 water and dust resistance and drop protection, which microSD cards fundamentally lack.

Industry analysts from the SD Association acknowledge that while SD Express aims to close the gap, thermal constraints and controller complexity make USB‑C SSDs far more practical for smartphones. External SSDs also bypass Android’s Scoped Storage limitations, enabling faster, more predictable file management without compromising system stability.

Ultimately, USB‑C storage is not about constant attachment but about intentional data movement. By treating external SSDs as high‑speed vaults rather than permanent extensions, users gain flexibility, reliability, and performance that legacy expandable storage can no longer offer.

AI Smartphones and Why Future Devices Demand Faster Built-In Storage

AI smartphones are no longer defined only by faster processors or better cameras. Instead, the true performance ceiling is increasingly determined by how quickly data can be read, written, and reused inside the device. As on-device AI becomes central to everyday smartphone experiences, built-in storage speed has shifted from a background specification to a mission-critical component.

Modern AI features such as real-time translation, generative photo editing, voice summarization, and context-aware assistants rely on large AI models stored locally. According to Samsung Semiconductor and Kioxia’s technical disclosures, these models are repeatedly loaded into memory, updated, and cached during inference. If storage throughput or latency is insufficient, even a powerful NPU cannot sustain smooth AI execution.

This is why flagship AI smartphones standardize on UFS 4.0-class storage rather than expandable media. UFS is designed for low-latency, high-parallel workloads, which closely resemble AI inference patterns. In contrast, removable storage was originally optimized for sequential media playback, not for rapid, random access to thousands of small parameter files.

Storage Type Typical Read Speed Random Access (IOPS) AI Suitability
UFS 4.0 (Built-in) Up to 4,200 MB/s ~500,000+ Excellent
microSD (UHS-I) ~90 MB/s ~4,000 Limited

The gap here is not incremental but structural. Google’s Android engineering team has repeatedly emphasized that AI-driven features benefit most from predictable, low-latency storage paths. This is also one reason why Android’s architecture increasingly isolates external storage from application execution. The OS itself implicitly assumes that critical AI resources reside on fast, internal flash.

Another overlooked factor is energy efficiency. AI workloads are sustained rather than bursty, meaning storage is accessed continuously during tasks such as live translation or camera-based recognition. UFS operates at significantly lower signaling voltages than SD-based solutions, reducing power draw and heat. For thin smartphones already managing SoC and NPU thermals, this difference directly affects performance stability.

From a user perspective, the benefits are tangible. Faster built-in storage enables near-instant AI responses, consistent camera performance during computational photography, and smoother multitasking with AI running in the background. What feels like “smart AI” to the user is, at a technical level, the absence of storage bottlenecks.

As AI models continue to grow in size and complexity, future devices will demand not just more storage, but fundamentally faster storage. This trajectory makes clear why AI smartphones are abandoning expandable solutions in favor of tightly integrated, ultra-fast internal flash as a core pillar of the next mobile computing era.

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