I wasted money on the wrong ESP board because nobody explained this upfront

The ESP32 is a fantastic little board. You can use it to fix your Wi-Fi deadzones in 15 minutes or even convert it into the perfect little travel router. However, while ESP32 boards might look the same, they can be very different under the surface—and that difference can leave your project dead in its tracks.

I own several of them, but I always bought my ESP32s thinking they’re all the same. Turns out, getting the wrong board can make all the difference, especially if you’re working on something that requires memory or involves a heavier workload.

Not every ESP32 board is created equal

The naming chaos hiding major hardware differences

The confusion starts with the naming itself. Espressif, the company behind the ESP32 family, has released multiple generations of chips under the ESP32 umbrella. They look the same, but if you look closely, they’re differentiated by different suffixes like S2, S3, C3, and more.

When people casually say ESP32-S, they usually mean the ESP32-S2 (or often the ESP32-S3). They’re not minor hardware revisions either. These are completely distinct chips with their own unique capabilities and different hardware requirements.

The original ESP32, launched in 2016, is a dual-core chip built on a Tensilica Xtensa LX6 processor running at up to 240 MHz, packed with 520 KB of SRAM, and comes equipped with both Wi-Fi and Bluetooth (Classic and BLE). The ESP32-S2 is a single-core chip based on an LX7 processor, has only 320 KB of SRAM, and, more importantly, no Bluetooth capabilities at all. The ESP32-S3, however, comes with a dual-core LX7 processor and adds Bluetooth 5.0, but only supports BLE. Crucially, it’s an entirely different beast when it comes to external RAM, often coming with up to 8 MB (or more) of PSRAM, which can make all the difference.

Unfortunately, none of this is obvious from a product listing that simply labels each chip as an “ESP32 module.”

PSRAM changes everything

The feature that decides whether projects actually work

When things get really confusing is when you’re working with projects like ESP32 AdBlocker. IF you want to turn your ESP32 into a DNS sinkhole to block ads and trackers, you want a board with at least 4 MB of PSRAM, not just any ESP32 board you’ll find on the market.

PSRAM is a type of external RAM that expands the chip’s usable memory far beyond the on-die SRAM. ESP32 AdBlocker’s GitHub documentation clearly states that it requires an ESP32-S3 with 8MB PSRAM to host a full-sized blocklist, while a standard ESP32 with 4MB PSRAM may truncate it. Both versions technically work, but only if they have PSRAM.

And that’s where the problem lies. Just because you have an ESP32 board doesn’t mean it comes with PSRAM—meaning you may or may not be able to use it for this project. The S3 is also roughly twice as fast as the original ESP32 for this kind of workload, with domain search times under 50 microseconds as claimed by the project’s documentation.

Buy the wrong board—a bare-bones ESP32-S2 without PSRAM—and the project simply won’t run properly. Even if you’re able to flash the code onto the board by making the required changes in the Arduino IDE, it just doesn’t have the hardware to run the project properly. You won’t see any clear errors either because the board will likely get stuck in a boot loop that crashes before it can report any usable error message in the Serial Monitor.

Online listings make this way harder than it should be

Confusing specs, misleading labels, and missing details everywhere

The problem isn’t just Espressif’s naming either. Retailers further complicated the confusion by using inconsistent umbrella terms like ESP32 Devkit, ESP32-S Devkit, or ESP32-S3 Devkit, among others, all of which show up in the same search results.

There’s also the PSRAM variance within the same chip generation. The original ESP32 comes in variants with and without PSRAM. The WROVER module includes it; the more common (and often cheaper)WROOM doesn’t. So you can end up with a technically correct original ESP32 board that’s still useless for PSRAM-dependent projects because you accidentally bought the wrong module variant. An ESP32 can do a lot for your home network, but not if you buy the wrong one.

The easiest way to get it right is to read the project’s hardware requirements before you buy the board. As a general rule, the original ESP32 in a WROVER variant comes with 4 MB PSRAM and works for most moderate-complexity projects. The ESP32-S3 with 8MB PSRAM is the best choice for DNS sinkholes and large-dataset projects, while the ESP32-S2 is better suited for USB OTG and power-sensitive applications where Bluetooth isn’t needed. The C3 or C5 variants work everywhere else, especially in simple, low-power sensor roles.

Check your ESP before you buy

A quick checklist that saves money and frustration

So before you buy your next (or first) ESP32 board, ask yourself three things. Does the project require Bluetooth? If yes, rule out the ESP32-S2 entirely. Does the project need PSRAM? If yes, look explicitly for the WROVER or an S3 board that specifies onboard PSRAM. Last but not least, if the project specifies using a specific board or chip variant in its hardware notes, trust that over the product title.

The ESP32 ecosystem is quite exciting, and these tiny boards are capable of a lot, regardless of which version you end up buying. But that low cost comes with a naming disaster that most tutorials don’t clarify. Spend the extra five minutes reading documentation before you buy, and you’ll save yourself the frustration of waiting for a new board to arrive while you stare at the perfectly functional, but technically wrong one in your hand.