Project Overview
ESP32-S3 vs ESP32-C3 vs ESP32-C6: This guide compares the ESP32-S3, ESP32-C3, and ESP32-C6 modules so you can pick the right modern ESP32 variant for your project goals, like low-power BLE sensors, WiFi 6 battery nodes, or camera and UI builds.
The original ESP32-WROOM-32 launched in 2016 and dominated the maker world for years. Espressif has since shipped three modern variants: the ESP32-S3 (high-end Xtensa, 8 MB PSRAM, AI), the ESP32-C3 (cheap single-core RISC-V), and the ESP32-C6 (RISC-V plus WiFi 6, Zigbee, Thread). They share the Arduino IDE ecosystem and most of the same code, but they target completely different projects.
This guide focuses on practical buying decisions: specs side-by-side, real-world implications, and which variant fits common maker projects.
- Time: 10 to 20 minutes
- Skill level: Beginner
- What you will build: A clear decision framework for choosing ESP32-S3, ESP32-C3, or ESP32-C6 for your next IoT project
Parts List
From ShillehTek
- ESP-WROOM-32 (original) - for reference comparison
- XIAO ESP32-S3 - S3 baseline for PSRAM and higher-end features
- XIAO ESP32-C3 - low-cost BLE-first option with native USB
- XIAO ESP32-C6 - WiFi 6 plus 802.15.4 (Zigbee/Thread) option
External
- USB-C cables
- Arduino IDE 2.x with the Espressif boards package >= 3.0
Note: Board features and pin counts can vary by dev board. Native USB support depends on the specific ESP32 variant and how the board is routed.
Step-by-Step Guide
Step 1 - Compare headline specs side-by-side
Goal: Understand the biggest spec differences that drive real project outcomes.
What to do: Use the table below to match each variant to your priorities: PSRAM for graphics and ML, 802.15.4 for Zigbee/Thread, and USB capabilities for device-mode projects.
| ESP-WROOM-32 | ESP32-S3 | ESP32-C3 | ESP32-C6 | |
|---|---|---|---|---|
| CPU arch | Dual Xtensa LX6 | Dual Xtensa LX7 | Single RISC-V | Single RISC-V |
| Clock | 240 MHz | 240 MHz | 160 MHz | 160 MHz |
| WiFi | 2.4 GHz n | 2.4 GHz n | 2.4 GHz n | 2.4 GHz ax (WiFi 6) |
| Bluetooth | BT 4.2 + BLE 4.2 | BLE 5 | BLE 5 | BLE 5 |
| Zigbee / Thread | - | - | - | Yes (802.15.4) |
| PSRAM (typical) | 0 | 8 MB | 0 | 0 |
| Flash (typical) | 4 MB | 16 MB | 4 MB | 4 MB |
| Native USB | No (CP2102) | Yes (USB-OTG) | Yes | Yes |
| AI vector ops | No | Yes | No | No |
| Camera interface | Yes (DCMI) | Yes | No | No |
| GPIO count | 34 | 45 | 22 | 30 |
| Price (XIAO) | $8 | $8 | $5 | $8 |
Expected result: You can quickly see why S3 is the "big memory" pick, C3 is the low-cost BLE pick, and C6 is the WiFi 6 plus Zigbee/Thread pick.
Step 2 - Pick a default variant for a new IoT project
Goal: Make a fast first choice, then refine based on constraints.
What to do: Use this cheat sheet when you are starting fresh and do not yet know what to prioritize.
- Sensor node / button / battery-powered thing that talks to your phone - ESP32-C3. Cheapest, BLE 5, native USB, plenty fast.
- Smart-home device that lives on Zigbee or Matter / Thread - ESP32-C6. Only variant with 802.15.4 radio.
- Camera, large LCD UI, ML inference, audio - ESP32-S3. The 8 MB PSRAM is the main reason.
- Existing project with library compatibility concerns - original WROOM-32. The longest tutorial trail.
Expected result: You have a clear short list based on your project type.
Step 3 - Decide if WiFi 6 on the ESP32-C6 matters for you
Goal: Understand why WiFi 6 can matter even when raw speed is similar.
What to do: If you are building a battery-powered WiFi sensor, evaluate whether you want WiFi 6 features like Target Wake Time. The C6 can negotiate exactly when to wake up, helping battery-powered WiFi devices last years instead of months in the right design.
Expected result: You know whether to choose C6 specifically for power behavior on WiFi, not for peak throughput.
Step 4 - Factor in native USB capabilities
Goal: Choose the right chip if you want true USB device behavior over USB-C.
What to do: Remember that the original WROOM-32 commonly uses a CP2102 (or similar) USB-to-UART chip on dev boards. The newer S3/C3/C6 have native USB peripherals, which can enable USB-CDC for serial, USB-HID for keyboards and mice, and USB-MSC for mass storage. The S3 USB is the most capable (high-speed OTG); the C3/C6 USBs are full-speed only.
Expected result: You can choose S3 when USB feature depth matters, and C3/C6 when full-speed USB is enough.
Step 5 - Decide whether RISC-V vs Xtensa affects your project
Goal: Avoid over-optimizing for CPU architecture when it does not change your build.
What to do: For most Arduino projects, the core and code feel very similar. Differences usually show up in areas like:
- Toolchain ecosystem: RISC-V has better LLVM and Rust support; Xtensa is improving but more proprietary.
- Vector instructions: only the S3 (Xtensa LX7) has them, which is why it is the AI-friendly variant.
- Per-MHz performance: roughly comparable for embedded workloads.
- Power per task: RISC-V tends to be slightly more power-efficient at low clock speeds.
Expected result: You pick based on radios, memory, and peripherals first, then use architecture as a tie-breaker.
Step 6 - Map common projects to the right ESP32 variant
Goal: Sanity-check your choice against real-world examples.
What to do: Compare your project to the closest match below.
- Battery-powered DHT22 + BLE node - C3. $5 board, 5 µA deep sleep, BLE 5.
- Smart Matter / Thread switch - C6. Native 802.15.4.
- ESP32-CAM-style camera with face recognition - S3. PSRAM plus vector ops.
- LVGL touchscreen dashboard - S3. The framebuffer fits in PSRAM.
- Beginner’s first IoT project, follows a 5-year-old tutorial - original WROOM-32.
Expected result: You end with the right default board for your feature set and budget.
Conclusion
The classic ESP32-WROOM-32 still works, but for new builds you will usually be choosing among ESP32-S3, ESP32-C3, or ESP32-C6. The C3 is the budget BLE-IoT default, the C6 is the future-proof pick when you need Zigbee/Thread (and WiFi 6 power features), and the S3 is the heavyweight option for camera, ML, audio, and large UIs thanks to PSRAM.
Want the exact boards used in this comparison? Grab them from ShillehTek.com. If you want help picking the right ESP32 for your product or designing an IoT build around it, check out our IoT consulting services.
Attribution: This guide was inspired by "Build Custom ESP32 Boards From Scratch | the Complete Guide to Designing Your Own ESP32-S3 and C3" on Instructables.
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