Single-board computers (SBCs) and embedded systems like Raspberry Pi, Arduino, and NVIDIA Jetson have become essential for hobbyists, educators, and industrial applications. Unlike traditional PCs, these devices have unique memory constraints. This guide covers what you need to know about memory in the embedded world.
Raspberry Pi Memory Specifications
Raspberry Pi models come with fixed, soldered LPDDR RAM that cannot be upgraded. Choose the right model at purchase time.
| Model | RAM | RAM Type | Storage | Use Case |
|---|---|---|---|---|
| Pi 5 (8GB) | 8GB | LPDDR4X-4267 | microSD / NVMe (via HAT) | Desktop replacement, media server, AI |
| Pi 5 (4GB) | 4GB | LPDDR4X-4267 | microSD / NVMe (via HAT) | General projects, home automation |
| Pi 5 (2GB) | 2GB | LPDDR4X-4267 | microSD / NVMe (via HAT) | Headless servers, IoT |
| Pi 4 (8GB) | 8GB | LPDDR4-3200 | microSD / USB SSD | Desktop use, Docker containers |
| Pi 4 (4GB) | 4GB | LPDDR4-3200 | microSD / USB SSD | Most projects, media centres |
| Pi 4 (2GB) | 2GB | LPDDR4-3200 | microSD / USB SSD | Basic projects, Pi-hole |
| Pi Zero 2 W | 512MB | LPDDR2 | microSD | IoT sensors, lightweight projects |
| Pi Pico | 264KB | On-chip SRAM | 2MB flash | Microcontroller projects |
NVIDIA Jetson for AI & ML
NVIDIA Jetson boards are designed for AI inference and machine learning at the edge. They feature shared CPU/GPU memory:
| Model | RAM | GPU | Use Case |
|---|---|---|---|
| Jetson Orin Nano 8GB | 8GB LPDDR5 | 1024 CUDA cores | Entry AI development, computer vision |
| Jetson Orin NX 16GB | 16GB LPDDR5 | 1024 CUDA cores | Advanced AI, robotics, edge inference |
| Jetson AGX Orin 64GB | 64GB LPDDR5 | 2048 CUDA cores | Professional AI/ML, autonomous systems |
Storage Options for SBCs
Since SBC RAM is fixed, optimising storage is critical for performance:
- microSD cards: Cheapest but slowest. Use A2-rated cards (Samsung EVO Plus, SanDisk Extreme) for best random I/O
- USB SSD boot: Raspberry Pi 4/5 can boot from USB SSDs — dramatically faster than microSD
- NVMe HAT: Raspberry Pi 5 supports M.2 NVMe SSDs via official HAT — best performance option
- eMMC modules: Some SBCs (ODROID, Pine64) support eMMC storage — faster than microSD, more reliable
- Network boot: Pi can boot over network (PXE) — useful for clusters and centralised management
Arduino & Microcontrollers
Arduino and similar microcontrollers have very limited memory measured in kilobytes, not gigabytes:
| Board | SRAM | Flash | EEPROM |
|---|---|---|---|
| Arduino Uno R4 | 32KB | 256KB | 8KB |
| Arduino Mega 2560 | 8KB | 256KB | 4KB |
| Arduino Nano Every | 6KB | 48KB | 256 bytes |
| ESP32 | 520KB | 4MB (external) | — |
| ESP8266 | 80KB | 4MB (external) | — |
| Teensy 4.1 | 1MB | 8MB | 4KB |
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Frequently Asked Questions
Can I upgrade Raspberry Pi RAM?
No. All Raspberry Pi models have soldered LPDDR RAM that cannot be upgraded after manufacture. You must choose the RAM configuration at purchase time. The 8GB model is recommended for desktop use and Docker containers.
What is the best storage for Raspberry Pi?
For Raspberry Pi 5, an NVMe SSD via the official M.2 HAT offers the best performance. For Pi 4, a USB 3.0 SSD provides excellent speed. If using microSD, choose an A2-rated card like the Samsung EVO Plus for best random I/O performance.
Is 2GB enough for Raspberry Pi?
2GB is sufficient for headless servers (Pi-hole, Home Assistant), basic scripting, and IoT projects. For desktop use, web browsing, or running Docker containers, 4GB or 8GB is strongly recommended.
Can Arduino run out of memory?
Yes. Arduino SRAM is very limited (8KB on Mega, 32KB on Uno R4). Large arrays, strings, and complex programs can exhaust available memory, causing crashes or erratic behaviour. Use the F() macro to store strings in flash instead of SRAM.
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