In high-performance FPGA-based systems, selecting the right storage interface is crucial to address key requirements such as high bandwidth, low power consumption, optimal storage capacity, and minimal resource utilization. These storage needs vary widely from real-time data logging in edge devices to accelerating compute-intensive applications.
This article presents a comprehensive comparison of five prominent storage technologies NAND, SD 3.0, eMMC 5.1, SATA 3.0, and NVMe analysing their performance and suitability based on metrics relevant to FPGA applications.
At iWave, our in-house FPGA IP cores and expertise enable us to deliver optimized and efficient storage IP solutions tailored to customer requirements, helping accelerate project development and reduce time to market.
Resource Utilization
The FPGA logic resources consumed by each storage interface vary significantly, depending on the protocol complexity and hardware requirements. The main elements considered here are Look-Up Tables (LUTs), Flip-Flops (FFs), and transceiver usage.
- NAND is the most resource-efficient, consuming ~1100 LUTs and ~700 FFs.
- NVMe is the most demanding, requiring over 5000 LUTs and 7000+ FFs.
- SATA, eMMC, and SD 3.0 fall in the mid-range, with SD and eMMC using more resources than SATA.
- SATA and NVMe additionally needs the transceivers for its physical layer implementation
Real-World Performance
Performance varies drastically depending on how the interface is accessed either through a full File System (with drivers, OS layers, etc.) or a direct Test Driver (bare-metal or low-level firmware).
With File System:
With Test Driver:
Real-world performance is significantly influenced by system and protocol overheads—including drivers, protocol stacks, operating system, firmware, and CPU processing—which collectively reduce the net throughput. Additionally, factors such as CPU speed, DDR memory bandwidth, and cache performance further impact the overall efficiency.
Additionally, the programming time for the NAND contributes significantly to the overall latency, as indicated by the device’s busy period during which the protocol prohibits any data transfers.
With all the bottlenecks mentioned above, our storage cores are benchmarked against the performance metrics specified in the device datasheets, and there are no major deviations from those reference values.
3. Variants and Compatibility
Each technology supports specific configurations:
- NAND: Baremetal, Linux drivers; supports both SOC and non-SOC FPGAs.
- SD 3.0 / eMMC 5.1: Baremetal drivers for non-SOC and SD/eMMC drivers for SOC platforms.
- SATA: AHCI driver support for SOC FPGAs and test drivers for non-SOC platforms.
- NVMe: Compatible with both SOC and non-SOC platforms via test drivers.
4. Capacity and Form Factor
Recommendations
Choosing the right storage interface for FPGA applications requires a careful balance between performance, power efficiency, logic resource usage, and system complexity. Below are targeted recommendations based on specific application needs:
- For resource-constrained FPGA designs
Interfaces like NAND and SD 3.0 are well-suited for low-power, cost-sensitive applications where logic utilization must be minimal. These interfaces offer sufficient performance for data logging, boot loaders, and basic file storage, making them ideal for edge computing, industrial automation, and lightweight embedded systems.
- For mid-tier embedded systems demanding improved performance
eMMC 5.1 strikes a practical balance between throughput, power consumption, and board space. With support for up to 2TB and relatively low CPU overhead, it is a preferred choice for consumer electronics, infotainment, and industrial HMI applications where higher sustained read/write speeds are required.
- For high-performance, data-intensive workloads
SATA 3.0 and NVMe deliver robust performance capabilities. SATA 3.0 offers a stable and widely supported interface with good bandwidth (~450 MBps), while NVMe over PCIe Gen3/Gen4 provides ultra-fast data rates exceeding 5000 MBps, ideal for AI acceleration, high-resolution video processing, SSD-based RAID systems, and server-class embedded platforms. However, these come with higher complexity, increased FPGA logic usage, and the need for transceiver support.
Ultimately, the best storage interface is application dependent. Designers must weigh factors such as data rate requirements, latency tolerance, FPGA resource availability, system cost, and integration ease.
With over 25 years of embedded design expertise, iWave offers a rich portfolio of customizable storage IP cores tailored for FPGA applications. Our IP solutions are optimized for leading FPGA platforms (AMD, Altera & Microchip etc.) and are available under flexible licensing models including perpetual, project based ensuring faster time-to-market and seamless FPGA integration.
For more information feel free to contact us at mktg@iwave-global.com
