The Future of UFS: Beyond UFS 3.1

The Evolution of UFS Standards and Its Modern Significance The journey of Universal Flash Storage (UFS) is a testament to the relentless pursuit of faster, more...

Jul 16,2024 | SANDRA

The Evolution of UFS Standards and Its Modern Significance

The journey of Universal Flash Storage (UFS) is a testament to the relentless pursuit of faster, more efficient data handling in mobile and embedded systems. Born from the need to overcome the limitations of its predecessor, eMMC (embedded MultiMediaCard), UFS introduced a revolutionary serial interface and full-duplex communication, enabling simultaneous read and write operations. This was a paradigm shift from the half-duplex, parallel interface of eMMC. The standard has evolved through several iterations: UFS 2.0 brought significant speed improvements, UFS 2.1 added features like Host Performance Booster, and UFS 3.0 marked a major leap with doubled bandwidth and improved power efficiency. This evolution has been driven by the insatiable demands of modern applications—4K/8K video recording, high-resolution mobile gaming, AI-powered computational photography, and the rapid adoption of 5G connectivity, which all generate and consume vast amounts of data instantaneously. The significance of UFS in today's devices cannot be overstated; it is the silent workhorse that determines application load times, file transfer speeds, and overall system responsiveness. In markets like Hong Kong, where smartphone penetration is among the highest globally and consumers are early adopters of cutting-edge technology, the performance of internal storage is a critical purchasing factor. The transition to standards like has enabled flagship devices in the region to deliver desktop-class storage performance, fundamentally enhancing the mobile user experience and enabling new, data-intensive use cases that were previously confined to PCs.

A Recap of UFS 3.1: Features and Market Presence

Introduced in early 2020 by JEDEC, the UFS 3.1 specification built upon the solid foundation of UFS 3.0 by introducing three pivotal optional features designed to enhance real-world performance, reliability, and power management. First, Write Booster utilizes a small portion of high-speed SLC (Single-Level Cell) cache to dramatically accelerate write speeds for burst operations, such as shooting a burst of high-resolution photos or recording 8K video. Second, DeepSleep mode is a new low-power state that allows the storage device to consume significantly less power when the host is in sleep mode, a crucial feature for extending battery life in always-on mobile devices. Third, Performance Throttling Notification enables the UFS device to inform the host system when its temperature reaches a threshold that necessitates throttling performance to prevent overheating, allowing for more graceful thermal management. The standard also made Host Performance Booster (HPB) and Host Memory Buffer (HMB) features more mainstream. In terms of raw performance, UFS 3.1 drives can achieve sequential read speeds of over 2100 MB/s and write speeds exceeding 1200 MB/s. Market adoption has been swift, particularly in the flagship and high-end smartphone segments. Brands like Samsung, Xiaomi, OPPO, and OnePlus have widely adopted UFS 3.1 in their premium models. According to industry analyses focusing on the Asia-Pacific region, including Hong Kong, over 70% of smartphones priced above HKD 4,000 in 2022-2023 were equipped with UFS 3.1 storage. The technology has also begun penetrating other embedded markets, such as automotive infotainment systems, high-end drones, and VR/AR headsets, where fast data access is paramount.

Key Specifications of UFS 3.1 vs. Predecessors

Confronting the Challenges and Limitations of UFS 3.1

Despite its impressive capabilities, UFS 3.1 is not without its bottlenecks and areas ripe for improvement. One primary challenge is the interface bandwidth itself. While the 11.6 Gbps per lane (with support for 2 lanes) was groundbreaking, the explosion of data from higher-resolution sensors (200MP+ cameras), 8K video at 60fps, and advanced AI models is beginning to push against this limit. The MIPI M-PHY physical layer, while efficient for mobile, has inherent scalability constraints compared to interfaces like PCIe used in NVMe SSDs. Furthermore, the performance of UFS 3.1 is highly dependent on implementation. Features like Write Booster rely on a finite SLC cache; once this cache is saturated during sustained writes (like transferring a large 4K video file), write speeds can drop significantly to native TLC or QLC NAND speeds. Thermal management remains a critical issue in compact form factors; sustained high performance can lead to throttling, negating the speed advantages. UFS 3.1 also faces competition from other storage technologies. The most direct competitor is NVMe over PCIe, which dominates the PC and server markets and offers vastly higher bandwidth (with PCIe 4.0 and 5.0). While not directly comparable due to different form factors and power envelopes, the performance gap pressures UFS to evolve faster. Additionally, technologies like SD Express (leveraging PCIe and NVMe) aim to bring similar high performance to removable storage cards, potentially challenging the need for ultra-fast internal storage in some device categories. For the Hong Kong market, where consumers frequently use their devices for prolonged, intensive tasks like mobile live streaming and cloud gaming, these limitations in sustained performance and thermal behavior are becoming more noticeable.

Emerging Trends Shaping the Future of Storage

The storage landscape is being reshaped by several converging trends that will inevitably influence the next generation of UFS. Firstly, the influence of NVMe and high-performance interfaces is profound. The NVMe protocol, designed from the ground up for non-volatile memory over PCIe, sets a high bar for low latency, high queue depths, and parallelism. The mobile industry is keenly observing this, and future UFS standards are expected to adopt a similar command set or integrate more closely with PCIe-based physical layers for a unified storage architecture across devices. Secondly, advances in NAND flash memory continue at a rapid pace. The transition to 176-layer and beyond 200-layer 3D NAND structures increases density and can improve performance and power efficiency. However, the move to QLC (Quad-Level Cell) and PLC (Penta-Level Cell) for higher density comes with trade-offs in endurance and write speed, making controller intelligence and features like Write Booster even more critical. New memory technologies are also on the horizon, with 3D XPoint (Optane) and MRAM offering potential as high-speed caching layers or even primary storage in specialized applications. Finally, new storage architectures are emerging. Computational storage, where processing is done within the storage device itself to reduce data movement, and zoned storage, which optimizes for sequential writes (ideal for video), are concepts being explored for mobile and data center environments alike. These trends collectively point towards a future where storage is not just a passive repository but an active, intelligent, and ultra-high-performance component of the system.

Key Storage Technology Trends

• Interface Evolution: Convergence towards PCIe/NVMe-like efficiency in mobile form factors.
• NAND Innovation: Higher layer counts (200L+), QLC/PLC adoption, and improved endurance techniques.
• New Memory Types: Exploration of MRAM, ReRAM, and Phase-Change Memory for caching and specialized roles.
• Architectural Shifts: Computational storage, zoned namespaces (ZNS), and tighter integration with system-on-chip (SoC).

The Roadmap to UFS 4.0 and the Horizon Beyond

The official release of the UFS 4.0 standard by JEDEC in August 2022 provides a clear view of the immediate future, moving decisively beyond UFS 3.1. The most headline-grabbing improvement is a massive leap in interface speed. UFS 4.0 utilizes the new MIPI M-PHY 5.0 specification and UniPro 2.0 transport layer, doubling the per-lane bandwidth to 23.2 Gbps. With support for two lanes, this enables a theoretical maximum interface bandwidth of up to 46.4 Gbps (or ~5.8 GB/s), more than doubling the effective bandwidth of UFS 3.1. This translates to target sequential read speeds exceeding 4,200 MB/s and write speeds over 2,800 MB/s. Beyond raw speed, UFS 4.0 introduces significant improvements in power efficiency, boasting a 46% improvement in power per MB/s transferred compared to UFS 3.1, which is vital for battery life. It also supports the newer and more secure RPMB (Replay Protected Memory Block) standard for enhanced data security. Form factor support includes the new, more compact UFS 4.0 package (11.0 x 13.0 x 1.0mm). Looking further ahead, discussions for UFS 5.0 are already beginning, focusing on leveraging PCIe physical layers for even greater bandwidth scalability, potentially integrating computational storage capabilities, and further refining QoS (Quality of Service) for mixed workloads. These advancements will unlock potential applications in future devices such as true desktop-replacement smartphones, advanced AR glasses requiring instant access to vast 3D datasets, autonomous vehicle sensor fusion systems processing terabytes of data daily, and sophisticated robotics.

Transforming the Mobile and Embedded Industries

The progression from UFS 3.1 to UFS 4.0 and beyond will have a transformative impact on device design and user experience. For consumers, the enhancements will manifest as near-instantaneous app launches, seamless switching between heavy applications, and the ability to edit 8K video directly on a smartphone or tablet without frustrating lag. Cloud gaming services, like those tested and launched in tech-savvy markets such as Hong Kong, will benefit from drastically reduced loading times and more stable performance, making them virtually indistinguishable from local gameplay on mid-tier PCs. For innovators and manufacturers, this storage performance headroom opens new possibilities. Smartphone cameras can leverage faster storage to implement more complex multi-frame computational photography algorithms or record high-frame-rate 8K HDR video for extended durations. Foldable and rollable devices, which often act as both phone and tablet, will require and benefit from this high-speed storage to manage more demanding desktop-like workflows. In the embedded space, automotive systems will use faster UFS to enable richer, more responsive digital cockpits, instant-start infotainment, and rapid updates for Advanced Driver-Assistance Systems (ADAS). Industrial IoT devices and AI edge processors will leverage the speed to perform real-time analytics on locally stored data. The ripple effect will be a new wave of devices that are not just communication tools but powerful, portable computing hubs.

A Bright Future Fueled by Continuous Innovation

The trajectory of Universal Flash Storage, from its inception to the widespread adoption of UFS 3.1 and the promising dawn of UFS 4.0, illustrates a dynamic and critical field of technological advancement. The storage subsystem is no longer a mere commodity; it is a key differentiator that defines the capabilities of modern smart devices. While UFS 3.1 has successfully met the demands of the current flagship ecosystem, the relentless growth in data creation and consumption necessitates continuous innovation. The collaboration within JEDEC, alongside the R&D efforts of major semiconductor companies in South Korea, the United States, and also in regions with strong tech manufacturing like Greater China (including Hong Kong's role in design and testing), ensures that the evolution of UFS will keep pace with, and even enable, future applications. The future of UFS is undoubtedly bright, characterized by staggering speeds, intelligent power management, and deeper system integration. This ongoing innovation is the key to unlocking the full potential of 5G, AI, and the metaverse, ensuring that our devices are not bottlenecks but enablers of the next digital revolution.