Since you are using a microcontroller, you'll most like interface to the card in SPI mode, which is perfectly fine for logging applications - not so much for faster applications like video recording. Your block size will be typically 512 bytes, so that's the minimum chunk of data that you'll be writing/reading in one go. Hello Everyone, I am working with an ESP32 Dev Kit (using ESP32 WROOM 32E) to be exact. The goal is to write to an SD card at the rate of around 12MegaBITS per second. So far i've just been using the default SPI with the default SD.h example. The serial monitor says i'm writing 1048576 bytes in around 4000-5000 ms. If I did the math right, thats only around 2Mbps where I need 12 as stated Support Serial Peripheral Interface (SPI) for firmware upgrade to SPI Flash Memory via USB interface; On-Chip power MOSFETs for all flash media cards power source; On-chip 5V to 3.3V and 3.3V to 1.2V regulator; On board 25 MHz Crystal driver circuit; Support USB 2.0 LPM (Link Power Management) Support USB 3.1 Gen 1 LTM (Latency Tolerance Messaging) Winbond's W25X and W25Q SpiFlash ® Multi-I/O Memories feature the popular Serial Peripheral Interface (SPI), densities from 512K-bit to 512M-bit, small erasable sectors and the industry's highest performance. The W25X family supports Dual-SPI, effectively doubling standard SPI clock rates. The W25Q family is a "superset" of the 25X family with .

spi flash vs sd card