Cheap ESP32-S3-WROOM-1-N16R8 or N8R2 modules with BAD / NO PSRAM #436
Description
REALLY, PAY ATTENTION WHAT S3 BOARD YOU ARE BUYING IF YOU COULD, USUALLY YOU COULDN'T!
$${\color{red}CHEAP \space ONES \space LIKELY \space HAVE \space BAD/QUADfused/NO \space PSRAM!}$$
Update (AI elaborated) explanation:
NxR2 -> QUAD PSRAM
NxR8/R16 --> OCTAL PSRAM
There are no QUAD 8MB or 16MB Espressif PSRAM chips, so there is no label / model you can rely on!
Simply. these "off-spec" PSRAM that should be discarded, but you would be happy to pay less and use them "somehow".
These are "B-grade" chips where the Octal interface didn't pass testing and was fused! to Quad.
It’s a dirty little secret in the Shenzhen "white-label" market. In the semiconductor world, it's called
binning, but for these cheap modules, it’s closer to salvaging.
No label, no info - nothing!
When Espressif (or their third-party SiP packagers) produces a batch, example of ESP32-S3R8 (the 8MB Octal version), some chips fail the high-speed Octal timing tests but work perfectly fine on the 4-bit Quad bus. Instead of throwing them away, they are sold as "off-spec" at a steep discount to bottom-tier board assemblers.
How they hide it from you:
Re-lasing: Some sketchy factories actually sand down the top of the chip and re-laser the part number to say ESP32-S3R8 even if the Octal bus is physically disabled or broken.
External PSRAM Hacks:
Some "8MB" boards use the base ESP32-S3 (no internal RAM) and solder a separate, cheaper 8MB Quad SPI RAM chip under the shield. Because it’s Quad, it performs like a turtle compared to the Octal SiP, but technically "has 8MB."
Voltage Mismatch:
They might use 3.3V Quad PSRAM on a board intended for 1.8V Octal, leading to the massive instability and heat you probably experienced before they died or you returned them.
The "Death" of GPIO 33-37:
The ultimate "Tell" is that Octal PSRAM must use GPIOs 33, 34, 35, 36, and 37.
If your board has pins 33-37 broken out to the side headers and you can use them for LEDs or sensors while "8MB PSRAM" is supposedly active, you’ve been scammed.
On a real Octal board, those pins are physically tied to the RAM bus and cannot be used for anything else.
If you want to verify the speed right now, you can check the ESP-IDF PSRAM Documentation to see how the clock rates differ; a "B-grade" chip will usually crash the moment you try to push it past 80MHz in the config.
---------------------------------------- ORIGINAL REQUEST -------------------------
Please help with the configuration / partitions etc, my S3 board keeps bootloops and I cannot use even the provided switch demo.
