WHICH RASPBERRY PI SHOULD YOU BUY? PI 5, PI 4, PI 3, ZERO, PICO AND COMPUTE MODULE EXPLAINED

Which Raspberry Pi Should You Buy? Pi 5, Pi 4, Pi 3, Zero, Pico and Compute Module Explained

Which Raspberry Pi Should You Buy? Pi 5, Pi 4, Pi 3, Zero, Pico and Compute Module Explained

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Walk into any engineering college lab in India, any small automation workshop, or any startup building a smart device, and you will find a Raspberry Pi somewhere on a bench. The trouble is that "a Raspberry Pi" now means at least six very different boards. Pick the wrong one and you either pay for power you never use, or you hit a wall halfway through the project and buy twice.

This guide explains what each board is actually good at, where it goes wrong, and which one to choose for the job in front of you. If you already know what you need, the full Raspberry Pi range at Tech Depot India lists every board and accessory in one place.

What people really use a Raspberry Pi for

Most Raspberry Pi projects fall into five groups. Knowing which group yours belongs to does most of the choosing for you.

  • Desktop and learning: a low-cost Linux computer for coding, school labs and home offices.
  • Home servers and networking: file servers, ad blockers, VPN gateways, media servers and small routers that run all day.
  • Cameras and vision: CCTV, number-plate reading, quality inspection on a production line, wildlife cameras.
  • IoT and automation: sensors, relays, data loggers, LoRaWAN and CAN bus gateways in farms, factories and vehicles.
  • Products and machines: kiosks, control panels, industrial HMIs and commercial devices sold in volume.

The first four are usually solved by a standard board. The last one is where the Compute Module and a copyright board come in, and it is the part most buyers get wrong.

Raspberry Pi 5: the default choice for anything that runs Linux

The Raspberry Pi 5 uses the Broadcom BCM2712, a quad-core Cortex-A76 at buy online raspberry pi 3 model b+ in India 2.4 GHz. In practice it is two to three times faster than the Pi 4, boots and installs software noticeably quicker, and is the first Pi that feels like a usable everyday desktop. It also adds a PCIe connector, which means you can run an NVMe SSD or an AI accelerator instead of relying on a microSD card.

The memory size is the main decision:

Two things catch new Pi 5 owners out. First, the board needs a proper 5V 5A supply; a phone charger will cause random reboots and USB devices that drop out. The official 27W USB-C power supply solves that. Second, the Pi 5 runs hot under sustained load and slows itself down. An Active Cooler keeps it at full speed, and the official Pi 5 case has a built-in fan for the same reason.

If you are starting from nothing, the Raspberry Pi 5 complete starter kit puts the board, power, cooling and storage in one box so nothing is missing on day one.

Raspberry Pi 4: still useful, for the right reasons

The Pi 4 is slower than the Pi 5, but it is not obsolete. It draws less power, runs cooler, works with a 15W supply, and has years of tested tutorials, HATs and software images behind it. If you are maintaining a project that already runs on a Pi 4, or a lab where every bench uses the same image, staying on Pi 4 saves you re-testing everything.

The Raspberry Pi 4 Model B 2GB suits single-task devices, while the Raspberry Pi 4 Model B 4GB handles light desktop use and small servers. Pair either with the official 15.3W Pi 4 power supply.

For a new project with no legacy to protect, the Pi 5 is almost always the better buy. For a step-by-step comparison, see the Raspberry Pi 5 beginner's guide for India.

Raspberry Pi 3: low-cost, low-power and still everywhere

Thousands of college labs, kiosks and classroom kits across India still run on the Raspberry Pi 3 family. It uses less power than a Pi 4 or Pi 5, needs no fan, and runs a huge library of older tutorials, HATs and software images without changes. If you are replacing a board in an existing setup, or building a simple single-purpose device on a tight budget, a Pi 3 is often all you need.

  • Raspberry Pi 3 Model B: quad-core 1.2 GHz, 1GB RAM, Wi-Fi and Bluetooth built in. A drop-in replacement for older lab and kiosk installations.
  • Raspberry Pi 3 Model B+: the faster 1.4 GHz version with dual-band Wi-Fi and quicker Ethernet, and support for a PoE HAT. The best Pi 3 for networked projects.
  • Raspberry Pi 3 Model A+: the same 1.4 GHz processor on a smaller, cheaper board with 512MB RAM and one USB port, for embedded builds where space matters.

For a ready-to-use setup, the Raspberry Pi 3B+ Official Kit and the Raspberry Pi 3B Complete Kit include the board and the essentials to get started straight away. For anything new that needs a desktop, a camera stream or AI, choose a Pi 4 or Pi 5 instead.

Raspberry Pi Zero 2 W: when size and power matter more than speed

The Zero 2 W is a quad-core Pi the size of a stick of chewing gum, with Wi-Fi and Bluetooth built in. It runs full Raspberry Pi OS, uses a fraction of the power of a Pi 5, and fits inside wearables, drones, battery-powered cameras and retro gaming handhelds.

Choose the Raspberry Pi Zero 2 W with header if you want to plug in HATs and jumper wires straight away, or the plain Raspberry Pi Zero 2 W if you will solder only the pins you need to save height. The trade-off is 512MB of RAM, so it is not a desktop machine.

Raspberry Pi Pico: not a computer, a microcontroller

This is the most common mix-up. The Pico does not run Linux. It runs one program written in MicroPython or C, starts instantly, never needs shutting down, and cannot corrupt an SD card because it has none. That makes it far more reliable than any Pi for reading sensors, driving motors and controlling relays.

  • Raspberry Pi Pico H: headers already soldered, ideal for breadboards and classrooms.
  • Raspberry Pi Pico W: adds Wi-Fi for IoT sensors that report to a dashboard or phone.
  • Raspberry Pi Pico 2: the newer RP2350 chip with more speed, more memory and security features for commercial products.

A good rule: if your project needs a screen, a browser or a camera stream, use a Pi. If it needs to read a sensor and switch something on reliably for years, use a Pico. Many real systems use both, with the Pico doing the hardware work and the Pi doing the networking.

Compute Module and copyright boards: for products, not prototypes

A standard Pi is a finished board with fixed ports in fixed places. That is perfect on a bench and awkward inside a product. The Compute Module takes the same processor and memory and puts them on a small module with no connectors at all. You then plug it into a copyright board that has exactly the ports your product needs: two Ethernet ports for a router, a 4G modem for a remote gateway, a touchscreen for a control panel, or industrial power input for a factory.

Why businesses choose this route:

  • Onboard eMMC storage instead of a microSD card that can fail after a power cut.
  • Only the ports you need, so the enclosure is smaller, cheaper and more rugged.
  • Long production life, so a product you design today can still be built years from now.
  • Swap the module, keep the copyright, which makes upgrades and repairs fast.

The Raspberry Pi Compute Module 5 Lite 8GB brings Pi 5 performance to this format. The Lite version boots from an SD card or NVMe drive on the copyright, which suits designs that need large or replaceable storage.

For Compute Module 4 builds, the copyright board decides the product:

If you are new to this format, this explainer on the Raspberry Pi Compute Module 4 IO board shows how a module and copyright fit together before you design your own.

The accessories that turn a board into a working system

The board is only part of the build. These are the add-ons that decide whether a project works in the field:

Quick answer: which board for which job

  • Learning, coding, desktop: Pi 5 4GB or 8GB.
  • Home server, Home Assistant, NAS: Pi 5 8GB with active cooling.
  • AI camera or object detection: Pi 5 8GB plus the AI Kit and Camera Module 3.
  • Existing Pi 4 project: stay on Pi 4.
  • Replacing an old lab or kiosk board, or a low-cost single-purpose device: Pi 3 Model B, B+ or A+.
  • Small, battery-powered or wearable: Zero 2 W.
  • Sensors, motors, relays: Pico, Pico W or Pico 2.
  • A product you will build in volume: Compute Module 5 or CM4 on a copyright board.
  • Router, firewall or 4G gateway: CM4 on a dual-Ethernet copyright board.

Where to buy Raspberry Pi boards and accessories online in India

Every board, copyright board and accessory in this guide is available from Tech Depot India with a GST invoice:

Still unsure? Start from the job, not the specifications. Write down what the device must do, where it will live and whether you plan to sell more than one. That answer points to the right board almost every time. When you are ready, every board and accessory mentioned here is listed at Tech Depot India.

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