Raspberry Pi Models Compared: Pi 5, Pi 4, CM4, Zero 2W, and Pico

The Raspberry Pi name covers a wide range of hardware — from a quad-core Linux computer capable of running a full desktop to a microcontroller smaller than a postage stamp. Picking the right model starts with understanding which device class fits your application.

Two Device Classes Under One Brand

If your application needs Linux — a web server, a Node.js application, a Python data pipeline, camera vision — choose an SBC. If your application needs precise hardware timing, GPIO interrupt response in microseconds, or a simple control loop without OS overhead, the Pico is appropriate. For applications needing both, the common pattern is a Pi SBC paired with a Pico or other MCU as a real-time co-processor; see Real-Time Control on Raspberry Pi: the Co-Processor Pattern.

Raspberry Pi 5

• SoC: BCM2712 (Arm Cortex-A76, quad-core, up to 2.4 GHz)
• RAM: 2 GB, 4 GB, or 8 GB LPDDR4X
• Storage: MicroSD; PCIe 2.0 connector (enables M.2 NVMe HAT for SSD)
• Networking: Gigabit Ethernet, Wi-Fi 5 (802.11ac), Bluetooth 5.0
• Display/camera: 2× MIPI CSI (camera), 2× MIPI DSI (display), 2× HDMI 2.0 (up to 4Kp60)
• USB: 2× USB 3.0, 2× USB 2.0
• Power: Requires 5V/5A USB-C supply (official 27W supply recommended)
• GPIO: 40-pin header, compatible with Pi 4 HATs (verify peripheral compatibility — see FAQ)

Best for: Computationally intensive Linux applications: video processing, local inference, dense I/O multiplexing, or anything that saturates a Pi 4. The PCIe interface enables NVMe storage that is far more reliable and performant than microSD, making the Pi 5 more attractive for demanding embedded Linux deployments. The Pi 5 uses the most power of any Pi SBC and requires active cooling under sustained load.

Raspberry Pi 4 Model B

• SoC: BCM2711 (Arm Cortex-A72, quad-core, up to 1.8 GHz)
• RAM: 1 GB, 2 GB, 4 GB, or 8 GB LPDDR4
• Storage: MicroSD
• Networking: Gigabit Ethernet, Wi-Fi 5, Bluetooth 5.0
• Display: 2× micro-HDMI (up to 4Kp60)
• USB: 2× USB 3.0, 2× USB 2.0
• GPIO: 40-pin header

Best for: The Pi 4B is the most widely deployed Pi SBC and has the deepest accessory and HAT ecosystem. If existing Pi 4 HATs, camera modules, or software configurations are a dependency, the Pi 4 is the safe starting point. For new designs where the SoC differences matter, the Pi 5 now occupies the same compute tier with better I/O. The Pi 4B remains the better choice where broad hardware compatibility is more important than peak performance.

Note on production use: the Pi 4B uses a microSD card for primary storage. SD cards are a known reliability risk in embedded applications — they are not designed for the sustained random-write patterns of an OS root filesystem. For prototyping the Pi 4B is fine; for production embedded products, the CM4 with eMMC is the appropriate choice.

Raspberry Pi Compute Module 4 (CM4)

• SoC: BCM2711 (same as Pi 4B)
• RAM: 1 GB, 2 GB, 4 GB, or 8 GB LPDDR4
• Storage: 8 GB, 16 GB, or 32 GB eMMC; or Lite variant (no eMMC, SD card on carrier)
• Form factor: SODIMM-style module mounting on a custom carrier board
• Connectivity: Wireless (Wi-Fi 5 + BT 5.0) or non-wireless variants
• Exposed interfaces on connector: PCIe Gen 2, USB 2.0 (two ports), HDMI, MIPI CSI/DSI, all GPIO

Best for: Embedded products. The CM4 separates the compute module from the I/O — the product designer builds a carrier board exposing only the interfaces the product needs, in the correct form factor. eMMC flash replaces the SD card, eliminating a reliability concern. The PCIe lane on the CM4 connector enables NVMe or other PCIe peripherals via carrier board. The absence of development-board ports (USB-A, 3.5mm, HDMI) keeps the final product BOM clean. For a full treatment of CM4 carrier board design, eMMC flashing with rpiboot, and RCM certification, see Should You Use the Raspberry Pi CM4 in a Product?.

The CM4 costs more than the Pi 4B and requires a carrier board investment, but for production volumes this is almost always the correct choice over using a Pi 4B in a product.

Raspberry Pi Zero 2 W

• SoC: RP3A0 (Arm Cortex-A53, quad-core, 1 GHz) — same core architecture as Pi 3
• RAM: 512 MB LPDDR2
• Storage: MicroSD
• Networking: Wi-Fi 4 (802.11n), Bluetooth 4.2
• Connectivity: 1× micro-USB OTG, 1× mini-HDMI, CSI camera connector
• GPIO: 40-pin (unpopulated pads on the board)
• Form factor: 65 mm × 30 mm — same footprint as the original Pi Zero
• Power: Typically around 0.4 W idle — significantly lower than Pi 4B or Pi 5

Best for: Compact, single-purpose Linux applications where the Pi 4's performance is unnecessary: a BLE/Wi-Fi sensor bridge, a camera over IP streamer, a small touch-screen controller, or any application where the Zero 2W's form factor (65mm × 30mm) enables a product that the larger Pi boards cannot fit. The 512 MB RAM is a meaningful constraint — applications that would use 1+ GB on a Pi 4 will not run well on the Zero 2W.

The Zero 2W is not well-suited for production embedded products without additional work — it uses SD card storage and the micro-USB OTG port for power and data is awkward for fixed installations. For compact production designs, a CM4 Lite with a minimal carrier is often a better path.

Raspberry Pi Pico and Pico 2

The Pico and Pico 2 are microcontroller development boards — they share the Raspberry Pi brand but are architecturally different devices from the SBCs above.

Pico (RP2040)

• MCU: RP2040 (dual Arm Cortex-M0+, up to 133 MHz)
• RAM: 264 KB SRAM
• Flash: 2 MB QSPI NOR flash (off-chip, on the Pico board)
• Peripherals: 2× UART, 2× SPI, 2× I2C, 16× PWM, 3× 12-bit ADC, USB 1.1 device/host, PIO (Programmable I/O)
• Networking: None on base Pico; Pico W adds Wi-Fi 4 + BLE 4.2 (Infineon CYW43439)
• Programming: Raspberry Pi Pico C/C++ SDK, MicroPython, CircuitPython

Pico 2 (RP2350)

• MCU: RP2350 (dual Arm Cortex-M33 or dual RISC-V Hazard3, up to 150 MHz — selectable at boot)
• RAM: 520 KB SRAM
• Flash: 4 MB QSPI NOR flash (on-board)
• Key improvements over RP2040: Cortex-M33 (hardware FPU, TrustZone, DSP instructions), more SRAM, higher clock speed, improved power management, enhanced security features
• Networking: None on base Pico 2; Pico 2 W adds Wi-Fi + BT

Best for: Real-time control tasks, bit-banged protocols, precise PWM generation, fast GPIO response, or any application that would use an STM32 or similar MCU. The RP2040/RP2350's PIO (Programmable I/O) state machines are unique — they enable custom serial protocols (WS2812 LED driving, custom sensor interfaces) implemented in hardware without bit-banging in software. The Pico is commonly used as a real-time co-processor alongside a Pi SBC.

For a comparison of Pico (RP2040/RP2350) against other MCU families (STM32, ESP32, nRF52), see How Do You Choose the Right Microcontroller?.

Model Selection by Application

GPIO and Peripheral Compatibility

The Pi 5, Pi 4B, CM4, and Zero 2W all expose a 40-pin GPIO header with the same pin assignment (3.3V logic, 5V power, ground, and GPIO/UART/SPI/I2C/PWM). Most Pi 4-era HATs are physically compatible. However:

• The Pi 5 introduced the RP1 I/O controller chip, which changed how some peripheral buses are routed internally. Camera and display interfaces in particular behave differently on Pi 5 vs Pi 4.
• The CM4 exposes its GPIO (and additional signals) on the high-density connector to the carrier board — not a 40-pin header. A carrier board with a 40-pin socket is the CM4 equivalent.
• The Pico's 40-pin edge connector is entirely different — 3.3V logic on all GPIO, different pin assignment, and no compatibility with Pi HATs.

For detailed GPIO interfacing guidance across all Pi models — including level shifting requirements, I2C pull-up configuration on CM4 carrier boards, and device tree overlays for custom hardware — see How to Interface Sensors and Peripherals with Raspberry Pi GPIO.

If you're developing firmware or embedded Linux for a Raspberry Pi-based product, Zeus Design provides embedded software development across the Pi platform.